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http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#ooRexx
ooRexx
  if a[i] == .nil then say "Item" i "is missing"  
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#MontiLang
MontiLang
30 VAR length . 35 VAR height . FOR length 0 ENDFOR 1 0 ARR VAR list . length 1 - VAR topLen . FOR topLen 0 ENDFOR 1 ARR VAR topLst .   DEF getNeighbors 1 - VAR tempIndex . GET tempIndex SWAP tempIndex 1 + VAR tempIndex . GET tempIndex SWAP tempIndex 1 + VAR tempIndex . GET tempIndex SWAP . FOR 3 TOSTR ROT ENDFOR FOR 2 SWAP + ENDFOR ENDDEF   DEF printArr LEN 1 - VAR stLen . 0 VAR j . FOR stLen GET j TOSTR OUT . j 1 + VAR j . ENDFOR || PRINT . ENDDEF   FOR height FOR length 0 ENDFOR ARR VAR next . 1 VAR i . FOR length list i getNeighbors VAR last . i 1 - VAR ind . last |111| == IF : . next 0 INSERT ind ENDIF   last |110| == IF : . next 1 INSERT ind ENDIF   last |101| == IF : . next 1 INSERT ind ENDIF   last |100| == IF : . next 0 INSERT ind ENDIF   last |011| == IF : . next 1 INSERT ind ENDIF   last |010| == IF : . next 1 INSERT ind ENDIF   last |001| == IF : . next 1 INSERT ind ENDIF   last |000| == IF : . next 0 INSERT ind ENDIF clear i 1 + VAR i . ENDFOR next printArr . next 0 ADD APPEND . VAR list . ENDFOR
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#PicoLisp
PicoLisp
(scl 6)   (de leftRect (Fun X) (Fun X) )   (de rightRect (Fun X H) (Fun (+ X H)) )   (de midRect (Fun X H) (Fun (+ X (/ H 2))) )   (de trapezium (Fun X H) (/ (+ (Fun X) (Fun (+ X H))) 2) )   (de simpson (Fun X H) (*/ (+ (Fun X) (* 4 (Fun (+ X (/ H 2)))) (Fun (+ X H)) ) 6 ) )   (de square (X) (*/ X X 1.0) )   (de integrate (Fun From To Steps Meth) (let (H (/ (- To From) Steps) Sum 0) (for (X From (>= (- To H) X) (+ X H)) (inc 'Sum (Meth Fun X H)) ) (*/ H Sum 1.0) ) )   (prinl (round (integrate square 3.0 7.0 30 simpson)))
http://rosettacode.org/wiki/Ordered_words
Ordered words
An   ordered word   is a word in which the letters appear in alphabetic order. Examples include   abbey   and   dirt. Task[edit] Find and display all the ordered words in the dictionary   unixdict.txt   that have the longest word length. (Examples that access the dictionary file locally assume that you have downloaded this file yourself.) The display needs to be shown on this page. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#VBScript
VBScript
Set objFSO = CreateObject("Scripting.FileSystemObject") Set infile = objFSO.OpenTextFile(objFSO.GetParentFolderName(WScript.ScriptFullName) & "\" &_ "unixdict.txt",1) list = "" length = 0   Do Until inFile.AtEndOfStream line = infile.ReadLine If IsOrdered(line) Then If Len(line) > length Then length = Len(line) list = line & vbCrLf ElseIf Len(line) = length Then list = list & line & vbCrLf End If End If Loop   WScript.StdOut.Write list   Function IsOrdered(word) IsOrdered = True prev_val = 0 For i = 1 To Len(word) If i = 1 Then prev_val = Asc(Mid(word,i,1)) ElseIf Asc(Mid(word,i,1)) >= prev_val Then prev_val = Asc(Mid(word,i,1)) Else IsOrdered = False Exit For End If Next End Function
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Vala
Vala
bool is_palindrome (string str) { var tmp = str.casefold ().replace (" ", ""); return tmp == tmp.reverse (); }   int main (string[] args) { print (is_palindrome (args[1]).to_string () + "\n"); return 0; }
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#JavaScript
JavaScript
const divMod = y => x => [Math.floor(y/x), y % x];   const sayNumber = value => { let name = ''; let quotient, remainder; const dm = divMod(value); const units = ['zero', 'one', 'two', 'three', 'four', 'five', 'six', 'seven', 'eight', 'nine', 'ten', 'eleven', 'twelve', 'thirteen', 'fourteen', 'fifteen', 'sixteen', 'seventeen', 'eighteen', 'nineteen']; const tens = ['', '', 'twenty', 'thirty', 'forty', 'fifty', 'sixty', 'seventy', 'eighty', 'ninety']; const big = [...['', 'thousand'], ...['m', 'b', 'tr', 'quadr', 'quint', 'sext', 'sept', 'oct', 'non', 'dec'].map(e => `${e}illion`)];   if (value < 0) { name = `negative ${sayNumber(-value)}` } else if (value < 20) { name = units[value] } else if (value < 100) { [quotient, remainder] = dm(10); name = `${tens[quotient]} ${units[remainder]}`.replace(' zero', ''); } else if (value < 1000) { [quotient, remainder] = dm(100); name = `${sayNumber(quotient)} hundred and ${sayNumber(remainder)}` .replace(' and zero', '') } else { const chunks = []; const text = []; while (value !== 0) { [value, remainder] = divMod(value)(1000); chunks.push(remainder); } chunks.forEach((e,i) => { if (e > 0) { text.push(`${sayNumber(e)}${i === 0 ? '' : ' ' + big[i]}`); if (i === 0 && e < 100) { text.push('and'); } } }); name = text.reverse().join(', ').replace(', and,', ' and'); } return name; };
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#IS-BASIC
IS-BASIC
100 PROGRAM "Reversal.bas" 110 RANDOMIZE 120 NUMERIC NR(1 TO 9) 130 LET TRIES=0 140 TEXT :PRINT "Given a jumbled list of the numbers 1 to 9, you must select how many digits from the left to reverse.":PRINT "Your goal is to get the digits in order with 1 on the left and 9 on the right.":PRINT 150 FOR I=1 TO 9 160 LET NR(I)=I 170 NEXT 180 DO 190 FOR I=2 TO 9 200 LET N=RND(I)+1 210 IF N<>I THEN CALL SWAP(N,I) 220 NEXT 230 LOOP WHILE ORDERED 240 DO 250 PRINT USING "##: ":TRIES; 260 FOR I=1 TO 9 270 PRINT NR(I); 280 NEXT 290 PRINT 300 IF ORDERED THEN EXIT DO 310 DO 320 INPUT PROMPT "How many numbers should be flipped? ":FLIP 330 LOOP WHILE FLIP<2 OR FLIP>9 340 FOR I=1 TO FLIP/2 350 CALL SWAP(I,FLIP-I+1) 360 NEXT 370 LET TRIES=TRIES+1 380 LOOP 390 PRINT :PRINT "You took";TRIES;"tries to put the digits in order." 400 DEF SWAP(A,B) 410 LET T=NR(A):LET NR(A)=NR(B):LET NR(B)=T 420 END DEF 430 DEF ORDERED 440 LET ORDERED=-1 450 FOR J=1 TO 8 460 IF NR(J)>NR(J+1) THEN LET ORDERED=0:EXIT FOR 470 NEXT 480 END DEF
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Oz
Oz
declare X in {Show X+2} %% blocks
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PARI.2FGP
PARI/GP
foo!='foo
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Nial
Nial
% we need a way to write a values and pass the same back wi is rest link [write, pass] % calculate the neighbors by rotating the array left and right and joining them neighbors is pack [pass, sum [-1 rotate, 1 rotate]] % calculate the individual birth and death of a single array element igen is fork [ = [ + [first, second], 3 first], 0 first, = [ + [first, second], 2 first], 1 first, 0 first ] % apply that to the array nextgen is each igen neighbors % 42 life is fork [ > [sum pass, 0 first], life nextgen wi, pass ]
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Nim
Nim
import random     type BoolArray = array[30, bool] Symbols = array[bool, char]     proc neighbours(map: BoolArray, i: int): int = if i > 0: inc(result, int(map[i - 1])) if i + 1 < len(map): inc(result, int(map[i + 1]))   proc print(map: BoolArray, symbols: Symbols) = for i in map: write(stdout, symbols[i]) write(stdout, "\l")   proc randomMap: BoolArray = randomize() for i in mitems(result): i = sample([true, false])     const num_turns = 20 symbols = ['_', '#']   T = true F = false   var map = [F, T, T, T, F, T, T, F, T, F, T, F, T, F, T, F, F, T, F, F, F, F, F, F, F, F, F, F, F, F]   # map = randomMap() # uncomment for random start   print(map, symbols)   for _ in 0 ..< num_turns: var map2 = map   for i, v in pairs(map): map2[i] = if v: neighbours(map, i) == 1 else: neighbours(map, i) == 2   print(map2, symbols)   if map2 == map: break map = map2
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#PL.2FI
PL/I
integrals: procedure options (main); /* 1 September 2019 */   f: procedure (x, function) returns (float(18)); declare x float(18), function fixed binary; select (function); when (1) return (x**3); when (2) return (1/x); when (3) return (x); when (4) return (x); end; end f;   declare (a, b) fixed decimal (10); declare (rect_area, trap_area, Simpson) float(18); declare (d, dx) float(18); declare (S1, S2) float(18); declare N fixed decimal (15), function fixed binary; declare k fixed decimal (7,2);   put (' Rectangle-left Rectangle-mid Rectangle-right' || ' Trapezoid Simpson'); do function = 1 to 4; select(function); when (1) do; N = 100; a = 0; b = 1; end; when (2) do; N = 1000; a = 1; b = 100; end; when (3) do; N = 5000000; a = 0; b = 5000; end; when (4) do; N = 6000000; a = 0; b = 6000; end; end;   dx = (b-a)/float(N);   /* Rectangle method, left-side */ rect_area = 0; do d = 0 to N-1; rect_area = rect_area + dx*f(a + d*dx, function); end; put skip edit (rect_area) (E(25, 15));   /* Rectangle method, mid-point */ rect_area = 0; do d = 0 to N-1; rect_area = rect_area + dx*f(a + d*dx + dx/2, function); end; put edit (rect_area) (E(25, 15));   /* Rectangle method, right-side */ rect_area = 0; do d = 1 to N; rect_area = rect_area + dx*f(a + d*dx, function); end; put edit (rect_area) (E(25, 15));   /* Trapezoid method */ trap_area = 0; do d = 0 to N-1; trap_area = trap_area + dx*(f(a+d*dx, function) + f(a+(d+1)*dx, function))/2; end; put edit (trap_area) (X(1), E(25, 15));   /* Simpson's Rule */ S1 = f(a+dx/2, function); S2 = 0; do d = 1 to N-1; S1 = S1 + f(a+d*dx+dx/2, function); S2 = S2 + f(a+d*dx, function); end; Simpson = dx * (f(a, function) + f(b, function) + 4*S1 + 2*S2) / 6; put edit (Simpson) (X(1), E(25, 15)); end;   end integrals;  
http://rosettacode.org/wiki/Ordered_words
Ordered words
An   ordered word   is a word in which the letters appear in alphabetic order. Examples include   abbey   and   dirt. Task[edit] Find and display all the ordered words in the dictionary   unixdict.txt   that have the longest word length. (Examples that access the dictionary file locally assume that you have downloaded this file yourself.) The display needs to be shown on this page. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Vedit_macro_language
Vedit macro language
File_Open("unixdict.txt", BROWSE) #1 = 2 // length of longest word found Repeat (ALL) { #2 = EOL_Pos-Cur_Pos // length of this word if (#2 >= #1) { #3 = 1 // flag: is ordered word Char(1) While (!At_EOL) { if (Cur_Char < Cur_Char(-1)) { #3 = 0 // not an ordered word break } Char(1) } if (#3) { // ordered word found if (#2 > #1) { // new longer word found #1 = #2 Reg_Empty(10) // clear list } BOL Reg_Copy(10,1,APPEND) // add word to list } } Line(1,ERRBREAK) // next word } Buf_Quit(OK) // close file Reg_Type(10) // display results
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#VBA
VBA
  Public Function isPalindrome(aString as string) as Boolean dim tempstring as string tempstring = Lcase(Replace(aString, " ", "")) isPalindrome = (tempstring = Reverse(tempstring)) End Function  
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Joy
Joy
  DEFINE units == [ "zero" "one" "two" "three" "four" "five" "six" "seven" "eight" "nine" "ten" "eleven" "twelve" "thirteen" "fourteen" "fifteen" "sixteen" "seventeen" "eighteen" "nineteen" ];   tens == [ "ten" "twenty" "thirty" "forty" "fifty" "sixty" "seventy" "eighty" "ninety" ];   convert6 == [1000000 <] [1000 div swap convert " thousand " putchars convert3] [1000000 div swap convert " million " putchars convert3] ifte;   convert5 == [null] [] [" and " putchars convert] ifte;   convert4 == [1000 <] [100 div swap units of putchars " hundred" putchars convert5] [convert6] ifte;   convert3 == [null] [] [32 putch convert] ifte;   convert2 == [100 <] [10 div swap pred tens of putchars convert3] [convert4] ifte;   convert == [20 <] [units of putchars] [convert2] ifte.  
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#J
J
require 'misc' NB. for the verb prompt   INTRO=: noun define Number Reversal Game Flip groups of numbers from the left of the list until the numbers are sorted in ascending order. )   reversegame=: verb define whilst. (-: /:~)nums do. nums=. 1+9?9 NB. 1-9 in random order end. score=. 0 smoutput INTRO NB. Display instructions while. -.(-: /:~)nums do. score=. 1+ score NB. increment score nnum=. 0".prompt (":score),': ',(":nums),' How many numbers to flip?: ' if. 0 = #nnum do. return. end. NB. exit on ENTER without number nums=. (C.i.-nnum) C. nums NB. reverse first nnum numbers end. 'You took ',(": score), ' attempts to put the numbers in order.' )
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Pascal
Pascal
print defined($x) ? 'Defined' : 'Undefined', ".\n";
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Perl
Perl
print defined($x) ? 'Defined' : 'Undefined', ".\n";
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#OCaml
OCaml
let get g i = try g.(i) with _ -> 0   let next_cell g i = match get g (i-1), get g (i), get g (i+1) with | 0, 0, 0 -> 0 | 0, 0, 1 -> 0 | 0, 1, 0 -> 0 | 0, 1, 1 -> 1 | 1, 0, 0 -> 0 | 1, 0, 1 -> 1 | 1, 1, 0 -> 1 | 1, 1, 1 -> 0 | _ -> assert(false)   let next g = let old_g = Array.copy g in for i = 0 to pred(Array.length g) do g.(i) <- (next_cell old_g i) done   let print_g g = for i = 0 to pred(Array.length g) do if g.(i) = 0 then print_char '_' else print_char '#' done; print_newline()
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#PureBasic
PureBasic
Prototype.d TestFunction(Arg.d)   Procedure.d LeftIntegral(Start, Stop, Steps, *func.TestFunction) Protected.d n=(Stop-Start)/Steps, sum, x=Start While x <= Stop-n sum + n * *func(x) x + n Wend ProcedureReturn sum EndProcedure   Procedure.d MidIntegral(Start, Stop, Steps, *func.TestFunction) Protected.d n=(Stop-Start)/Steps, sum, x=Start While x <= Stop-n sum + n * *func(x+n/2) x + n Wend ProcedureReturn sum EndProcedure   Procedure.d RightIntegral(Start, Stop, Steps, *func.TestFunction) Protected.d n=(Stop-Start)/Steps, sum, x=Start While x < Stop x + n sum + n * *func(x) Wend ProcedureReturn sum EndProcedure   Procedure.d Trapezium(Start, Stop, Steps, *func.TestFunction) Protected.d n=(Stop-Start)/Steps, sum, x=Start While x<=Stop sum + n * (*func(x) + *func(x+n))/2 x+n Wend ProcedureReturn sum EndProcedure   Procedure.d Simpson(Start, Stop, Steps, *func.TestFunction) Protected.d n=(Stop-Start)/Steps, sum1, sum2, x=Start Protected i For i=0 To steps-1 sum1+ *func(Start+n*i+n/2) Next For i=1 To Steps-1 sum2+ *func(Start+n*i) Next ProcedureReturn n * (*func(Start)+ *func(Stop)+4*sum1+2*sum2) / 6 EndProcedure   ;- Set up functions to integrate Procedure.d Test1(n.d) ProcedureReturn n*n*n EndProcedure   Procedure.d Test2(n.d) ProcedureReturn 1/n EndProcedure   ; This function should be integrated as a integer function, but for ; comparably this will stay as a float. Procedure.d Test3(n.d) ProcedureReturn n EndProcedure   ;- Test the code & present the results CompilerIf #PB_Compiler_Debugger MessageRequester("Notice!","Running this program in Debug-mode will be slow") CompilerEndIf   ; = 0.25 Define Answer$ Answer$="Left ="+StrD(LeftIntegral (0,1,100,@Test1()))+#CRLF$ Answer$+"Mid ="+StrD(MidIntegral (0,1,100,@Test1()))+#CRLF$ Answer$+"Right ="+StrD(RightIntegral(0,1,100,@Test1()))+#CRLF$ Answer$+"Trapezium="+StrD(Trapezium (0,1,100,@Test1()))+#CRLF$ Answer$+"Simpson ="+StrD(Simpson (0,1,100,@Test1())) MessageRequester("Answer should be 1/4",Answer$)   ; = Ln(100) e.g. ~4.60517019... Answer$="Left ="+StrD(LeftIntegral (1,100,1000,@Test2()))+#CRLF$ Answer$+"Mid ="+StrD(MidIntegral (1,100,1000,@Test2()))+#CRLF$ Answer$+"Right ="+StrD(RightIntegral (1,100,1000,@Test2()))+#CRLF$ Answer$+"Trapezium="+StrD(Trapezium (1,100,1000,@Test2()))+#CRLF$ Answer$+"Simpson ="+StrD(Simpson (1,100,1000,@Test2())) MessageRequester("Answer should be Ln(100), e.g. ~4.60517019",Answer$)   ; 12,500,000 Answer$="Left ="+StrD(LeftIntegral (0,5000,5000000,@Test3()))+#CRLF$ Answer$+"Mid ="+StrD(MidIntegral (0,5000,5000000,@Test3()))+#CRLF$ Answer$+"Right ="+StrD(RightIntegral (0,5000,5000000,@Test3()))+#CRLF$ Answer$+"Trapezium="+StrD(Trapezium (0,5000,5000000,@Test3()))+#CRLF$ Answer$+"Simpson ="+StrD(Simpson (0,5000,5000000,@Test3())) MessageRequester("Answer should be 12,500,000",Answer$)   ; 18,000,000 Answer$="Left ="+StrD(LeftIntegral (0,6000,6000000,@Test3()))+#CRLF$ Answer$+"Mid ="+StrD(MidIntegral (0,6000,6000000,@Test3()))+#CRLF$ Answer$+"Right ="+StrD(RightIntegral (0,6000,6000000,@Test3()))+#CRLF$ Answer$+"Trapezium="+StrD(Trapezium (0,6000,6000000,@Test3()))+#CRLF$ Answer$+"Simpson ="+StrD(Simpson (0,6000,6000000,@Test3())) MessageRequester("Answer should be 18,000,000",Answer$)
http://rosettacode.org/wiki/Ordered_words
Ordered words
An   ordered word   is a word in which the letters appear in alphabetic order. Examples include   abbey   and   dirt. Task[edit] Find and display all the ordered words in the dictionary   unixdict.txt   that have the longest word length. (Examples that access the dictionary file locally assume that you have downloaded this file yourself.) The display needs to be shown on this page. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Wren
Wren
import "io" for File import "/sort" for Sort   var words = File.read("unixdict.txt").split("\n") var longestLen = 0 var longest = [] for (word in words) { if (word.count > longestLen) { if (Sort.isSorted(word.toList)) { longestLen = word.count longest.clear() longest.add(word) } } else if (word.count == longestLen) { if (Sort.isSorted(word.toList)) longest.add(word) } } System.print("The %(longest.count) ordered words with the longest length (%(longestLen)) are:") System.print(longest.join("\n"))
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#VBScript
VBScript
function Squish( s1 ) dim sRes sRes = vbNullString dim i, c for i = 1 to len( s1 ) c = lcase( mid( s1, i, 1 )) if instr( "abcdefghijklmnopqrstuvwxyz0123456789", c ) then sRes = sRes & c end if next Squish = sRes end function   function isPalindrome( s1 ) dim squished squished = Squish( s1 ) isPalindrome = ( squished = StrReverse( squished ) ) end function
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#jq
jq
# Adapted from the go version. # Tested with jq 1.4 # # say/0 as defined here supports positive and negative integers within # the range of accuracy of jq, or up to the quintillions, whichever is # less. As of jq version 1.4, jq's integer accuracy is about 10^16.   def say:   # subfunction zillions recursively handles the thousands, # millions, billions, etc. # input: the number # i: which "illion" to use # sx: the string so far # output: the updated string def zillions(i; sx): ["thousand", "million", "billion", "trillion", "quadrillion", "quintillion"] as $illions | if . == 0 then sx else (. / 1000 | floor) | (. % 1000) as $p | zillions(i + 1; if $p > 0 then (($p | say) + " " + $illions[i]) as $ix | if sx != "" then $ix + ", " + sx else $ix end else sx end) end  ;   [ "", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"] as $small | ["ones", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"] as $tens   | if . == 0 then "zero" elif . < 0 then "minus " + (-(.) | say) elif . < 20 then $small[.] elif . < 100 then $tens[./10|floor] as $t | (. % 10) | if . > 0 then ($t + " " + $small[.]) else $t end elif . < 1000 then ($small[./100|floor] + " hundred") as $h | (. % 100) | if . > 0 then $h + " and " + (say) else $h end else # Handle values larger than 1000 by considering # the rightmost three digits separately from the rest: ((. % 1000) | if . == 0 then "" elif . < 100 then "and " + say else say end ) as $sx | zillions(0; $sx) end ;   say
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Java
Java
import java.util.List; import java.util.ArrayList; import java.util.Scanner; import java.util.Collections;     public class ReversalGame { private List<Integer> gameList;   public ReversalGame() { initialize(); }   public void play() throws Exception { int i = 0; int moveCount = 0; Scanner scanner = new Scanner(System.in); while (true) { System.out.println(gameList); System.out.println("Please enter a index to reverse from 2 to 9. Enter 99 to quit"); i = scanner.nextInt(); if (i == 99) { break; } if (i < 2 || i > 9) { System.out.println("Invalid input"); } else { moveCount++; reverse(i); if (isSorted()) { System.out.println("Congratulations you solved this in " + moveCount + " moves!"); break; } }   } scanner.close(); }   private void reverse(int position) { Collections.reverse(gameList.subList(0, position)); }   private boolean isSorted() { for (int i=0; i < gameList.size() - 1; ++i) { if (gameList.get(i).compareTo(gameList.get(i + 1)) > 0) { return false; } } return true; }   private void initialize() { this.gameList = new ArrayList<Integer>(9); for (int i=1; i < 10; ++i) { gameList.add(i); } while (isSorted()) { Collections.shuffle(gameList); } }     public static void main(String[] args) { try { ReversalGame game = new ReversalGame(); game.play(); } catch (Exception e) { System.out.println(e.getMessage()); e.printStackTrace(); } } }
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Phix
Phix
type nullableString(object o) return string(o) or o=NULL end type nullableString s s = "hello" s = NULL --s = 1 -- error --s = {1,2,3} -- error type nullableSequence(object o) return sequence(o) or o=NULL end type nullableSequence q q = {1,2,3} q = "string" -- fine (strings are a subset of sequences) q = NULL --q = 1 -- error
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PHL
PHL
if (obj == null) printf("obj is null!\n");
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Oforth
Oforth
: nextGen( l ) | i s | l byteSize dup ->s String newSize s loop: i [ i 1 if=: [ 0 ] else: [ i 1- l byteAt '#' = ] i l byteAt '#' = + i s if=: [ 0 ] else: [ i 1+ l byteAt '#' = ] + 2 if=: [ '#' ] else: [ '_' ] over add ] ;   : gen( l n -- ) l dup .cr #[ nextGen dup .cr ] times( n ) drop ;
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Python
Python
from fractions import Fraction   def left_rect(f,x,h): return f(x)   def mid_rect(f,x,h): return f(x + h/2)   def right_rect(f,x,h): return f(x+h)   def trapezium(f,x,h): return (f(x) + f(x+h))/2.0   def simpson(f,x,h): return (f(x) + 4*f(x + h/2) + f(x+h))/6.0   def cube(x): return x*x*x   def reciprocal(x): return 1/x   def identity(x): return x   def integrate( f, a, b, steps, meth): h = (b-a)/steps ival = h * sum(meth(f, a+i*h, h) for i in range(steps)) return ival   # Tests for a, b, steps, func in ((0., 1., 100, cube), (1., 100., 1000, reciprocal)): for rule in (left_rect, mid_rect, right_rect, trapezium, simpson): print('%s integrated using %s\n from %r to %r (%i steps) = %r' % (func.__name__, rule.__name__, a, b, steps, integrate( func, a, b, steps, rule))) a, b = Fraction.from_float(a), Fraction.from_float(b) for rule in (left_rect, mid_rect, right_rect, trapezium, simpson): print('%s integrated using %s\n from %r to %r (%i steps and fractions) = %r' % (func.__name__, rule.__name__, a, b, steps, float(integrate( func, a, b, steps, rule))))   # Extra tests (compute intensive) for a, b, steps, func in ((0., 5000., 5000000, identity), (0., 6000., 6000000, identity)): for rule in (left_rect, mid_rect, right_rect, trapezium, simpson): print('%s integrated using %s\n from %r to %r (%i steps) = %r' % (func.__name__, rule.__name__, a, b, steps, integrate( func, a, b, steps, rule))) a, b = Fraction.from_float(a), Fraction.from_float(b) for rule in (left_rect, mid_rect, right_rect, trapezium, simpson): print('%s integrated using %s\n from %r to %r (%i steps and fractions) = %r' % (func.__name__, rule.__name__, a, b, steps, float(integrate( func, a, b, steps, rule))))
http://rosettacode.org/wiki/Ordered_words
Ordered words
An   ordered word   is a word in which the letters appear in alphabetic order. Examples include   abbey   and   dirt. Task[edit] Find and display all the ordered words in the dictionary   unixdict.txt   that have the longest word length. (Examples that access the dictionary file locally assume that you have downloaded this file yourself.) The display needs to be shown on this page. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#XPL0
XPL0
string 0; \use zero-terminated strings int MaxLen, Pass, I, Ch, Ch0; char Word(25); def LF=$0A, CR=$0D, EOF=$1A; [FSet(FOpen("unixdict.txt", 0), ^I); MaxLen:= 0; for Pass:= 1 to 2 do [OpenI(3); repeat I:= 0; Ch0:= 0; loop [repeat Ch:= ChIn(3) until Ch # CR; \remove possible CR if Ch=LF or Ch=EOF then [if I > MaxLen then MaxLen:= I; if I=MaxLen & Pass=2 then [Word(I):= 0; Text(0, Word); CrLf(0)]; quit; ]; Word(I):= Ch; if Ch < Ch0 then [repeat Ch:= ChIn(3) until Ch=LF or Ch=EOF; quit; ]; Ch0:= Ch; I:= I+1; ]; until Ch = EOF; ]; ]
http://rosettacode.org/wiki/Ordered_words
Ordered words
An   ordered word   is a word in which the letters appear in alphabetic order. Examples include   abbey   and   dirt. Task[edit] Find and display all the ordered words in the dictionary   unixdict.txt   that have the longest word length. (Examples that access the dictionary file locally assume that you have downloaded this file yourself.) The display needs to be shown on this page. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#zkl
zkl
var words=L(), sz=0; // some state fcn isLex(word){ word.reduce(fcn(p,c){ (p<=c) and c or T(Void.Stop,False) }) } File("dict.txt").pump(Void,fcn(w){ w=w.strip(); // get rid of newline if(isLex(w)){ n:=w.len(); if(n>sz){ words.clear(w); sz=n } else if(n==sz) words.append(w) } }) println("Num words: %d, all size %d\n".fmt(words.len(),sz)); words.pump(Console.println);
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Vedit_macro_language
Vedit macro language
:PALINDROME: EOL #2 = Cur_Col-2 BOL for (#1 = 0; #1 <= #2/2; #1++) { if (CC(#1) != CC(#2-#1)) { Return(0) } } Return(1)
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Julia
Julia
const stext = ["one", "two", "three", "four", "five", "six", "seven", "eight", "nine"] const teentext = ["eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"] const tenstext = ["ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"] const ordstext = ["million", "billion", "trillion", "quadrillion", "quintillion", "sextillion", "septillion", "octillion", "nonillion", "decillion", "undecillion", "duodecillion", "tredecillion", "quattuordecillion", "quindecillion", "sexdecillion", "septendecillion", "octodecillion", "novemdecillion", "vigintillion"]   function normalize_digits!(a::Array{T,1}) where T<:Integer while 0 < length(a) && a[end] == 0 pop!(a) end length(a) end   function digits2text!(d::Array{T,1}, use_short_scale=true) where T<:Integer ndig = normalize_digits!(d) 0 < ndig || return "" if ndig < 7 s = "" if 3 < ndig t = digits2text!(d[1:3]) s = digits2text!(d[4:end]) * " thousand" 0 < length(t) || return s return occursin(t, "and") ? s * " " * t : s * " and " * t end if ndig == 3 s *= stext[pop!(d)] * " hundred" ndig = normalize_digits!(d) 0 < ndig || return s s *= " and " end 1 < ndig || return s*stext[pop!(d)] j, i = d j ≠ 0 || return s*tenstext[i] i ≠ 1 || return s*teentext[j] return s*tenstext[i] * "-" * stext[j] end s = digits2text!(d[1:6]) d = d[7:end] dgrp = use_short_scale ? 3 : 6 ord = 0 while dgrp < length(d) ord += 1 t = digits2text!(d[1:dgrp]) d = d[(dgrp+1):end] 0 < length(t) || continue t = t * " " * ordstext[ord] s = length(s) == 0 ? t : t * " " * s end ord += 1 t = digits2text!(d) * " " * ordstext[ord] 0 < length(s) || return t t * " " * s end   function num2text(n::T, use_short_scale=true) where T<:Integer -1 < n || return "minus "*num2text(-n, use_short_scale) 0 < n || return "zero" toobig = use_short_scale ? big(10)^66 : big(10)^126 n < toobig || return "too big to say" digits2text!(digits(n, base=10), use_short_scale) end
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#JavaScript
JavaScript
<html> <head> <title>Number Reversal Game</title> </head>   <body> <div id="start"></div> <div id="progress"></div> <div id="score"></div> <script type="text/javascript">
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PHP
PHP
$x = NULL; if (is_null($x)) echo "\$x is null\n";
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PicoLisp
PicoLisp
(if (not MyNewVariable) (handle value-is-NIL) )
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Pike
Pike
> mapping bar; > bar; Result: 0 > bar = ([ "foo":0 ]); > bar->foo; Result 0; > zero_type(bar->foo); Result: 0 > bar->baz; Result: 0 > zero_type(bar->baz); Result: 1
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Oz
Oz
declare A0 = {List.toTuple unit "_###_##_#_#_#_#__#__"}   MaxGenerations = 9   Rules = unit('___':&_ '__#':&_ '_#_':&_ '_##':&# '#__':&_ '#_#':&# '##_':&# '###':&_)   fun {Evolve A} {Record.mapInd A fun {$ I V} Left = {CondSelect A I-1 &_} Right = {CondSelect A I+1 &_} Env = {String.toAtom [Left V Right]} in Rules.Env end } end   fun lazy {Iterate X F} X|{Iterate {F X} F} end in for I in 0..MaxGenerations A in {Iterate A0 Evolve} do {System.showInfo "Gen. "#I#": "#{Record.toList A}} end
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#R
R
integ <- function(f, a, b, n, u, v) { h <- (b - a) / n s <- 0 for (i in seq(0, n - 1)) { s <- s + sum(v * f(a + i * h + u * h)) } s * h }   test <- function(f, a, b, n) { c(rect.left = integ(f, a, b, n, 0, 1), rect.right = integ(f, a, b, n, 1, 1), rect.mid = integ(f, a, b, n, 0.5, 1), trapezoidal = integ(f, a, b, n, c(0, 1), c(0.5, 0.5)), simpson = integ(f, a, b, n, c(0, 0.5, 1), c(1, 4, 1) / 6)) }   test(\(x) x^3, 0, 1, 100) # rect.left rect.right rect.mid trapezoidal simpson # 0.2450250 0.2550250 0.2499875 0.2500250 0.2500000   test(\(x) 1 / x, 1, 100, 1000) # rect.left rect.right rect.mid trapezoidal simpson # 4.654991 4.556981 4.604763 4.605986 4.605170   test(\(x) x, 0, 5000, 5e6) # rect.left rect.right rect.mid trapezoidal simpson # 12499998 12500003 12500000 12500000 12500000   test(\(x) x, 0, 6000, 6e6) # rect.left rect.right rect.mid trapezoidal simpson # 1.8e+07 1.8e+07 1.8e+07 1.8e+07 1.8e+07
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Visual_Basic_.NET
Visual Basic .NET
Module Module1   Function IsPalindrome(p As String) As Boolean Dim temp = p.ToLower().Replace(" ", "") Return StrReverse(temp) = temp End Function   Sub Main() Console.WriteLine(IsPalindrome("In girum imus nocte et consumimur igni")) End Sub   End Module
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Kotlin
Kotlin
// version 1.1.2   val oneNames = listOf( "", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen") val tenNames = listOf( "", "", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety") val thousandNames = listOf( "", "thousand", "million", "billion", "trillion", "quadrillion", "quintillion")   fun numToText(n: Long, uk: Boolean = false): String { if (n == 0L) return "zero" val neg = n < 0L val maxNeg = n == Long.MIN_VALUE var nn = if (maxNeg) -(n + 1) else if (neg) -n else n val digits3 = IntArray(7) for (i in 0..6) { // split number into groups of 3 digits from the right digits3[i] = (nn % 1000).toInt() nn /= 1000 } if (maxNeg) digits3[0]++   fun threeDigitsToText(number: Int): String { val sb = StringBuilder() if (number == 0) return "" val hundreds = number / 100 val remainder = number % 100 if (hundreds > 0) { sb.append(oneNames[hundreds], " hundred") if (remainder > 0) sb.append(if (uk) " and " else " ") } if (remainder > 0) { val tens = remainder / 10 val units = remainder % 10 if (tens > 1) { sb.append(tenNames[tens]) if (units > 0) sb.append("-", oneNames[units]) } else sb.append(oneNames[remainder]) } return sb.toString() }   val triplets = Array(7) { threeDigitsToText(digits3[it]) } var text = triplets[0] var andNeeded = uk && digits3[0] in 1..99 for (i in 1..6) { if (digits3[i] > 0) { var text2 = triplets[i] + " " + thousandNames[i] if (text != "") { text2 += if (andNeeded) " and " else ", " andNeeded = false } else andNeeded = uk && digits3[i] in 1..99 text = text2 + text } } return (if (neg) "minus " else "") + text }   fun main() { val exampleNumbers = longArrayOf( 0, 1, 7, 10, 18, 22, 67, 99, 100, 105, 999, -1056, 1000005000, 2074000000, 1234000000745003L, Long.MIN_VALUE ) println("Using US representation:") for (i in exampleNumbers) println("${"%20d".format(i)} = ${numToText(i)}") println() println("Using UK representation:") for (i in exampleNumbers) println("${"%20d".format(i)} = ${numToText(i, true)}") }
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#jq
jq
# Input: the initial array def play: def sorted: . == sort;   def reverse(n): (.[0:n] | reverse) + .[n:];   def prompt: "List: \(.list)\nEnter a pivot number: ";   def report: "Great! Your score is \(.score)";   {list: ., score: 0} | (if .list | sorted then "List was sorted to begin with." else prompt, ( label $done | foreach inputs as $n (.; .list |= reverse($n) | .score +=1; if .list | sorted then report, break $done else prompt end )) end);
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PL.2FI
PL/I
  declare x fixed decimal (10); ... if ^valid(x) then signal error;   declare y picture 'A9XAAA9'; ... if ^valid(y) then signal error;  
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PowerShell
PowerShell
if ($null -eq $object) { ... }
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#PureBasic
PureBasic
If variable = #Null Debug "Variable has no value" EndIf
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#PARI.2FGP
PARI/GP
step(v)=my(u=vector(#v),k);u[1]=v[1]&v[2];u[#u]=v[#v]&v[#v-1];for(i=2,#v-1,k=v[i-1]+v[i+1];u[i]=if(v[i],k==1,k==2));u;
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Racket
Racket
  #lang racket (define (integrate f a b steps meth) (define h (/ (- b a) steps)) (* h (for/sum ([i steps]) (meth f (+ a (* h i)) h))))   (define (left-rect f x h) (f x)) (define (mid-rect f x h) (f (+ x (/ h 2)))) (define (right-rect f x h)(f (+ x h))) (define (trapezium f x h) (/ (+ (f x) (f (+ x h))) 2)) (define (simpson f x h) (/ (+ (f x) (* 4 (f (+ x (/ h 2)))) (f (+ x h))) 6))   (define (test f a b s n) (displayln n) (for ([meth (list left-rect mid-rect right-rect trapezium simpson)] [name '( left-rect mid-rect right-rect trapezium simpson)]) (displayln (~a name ":\t" (integrate f a b s meth)))) (newline))   (test (λ(x) (* x x x)) 0. 1. 100 "CUBED") (test (λ(x) (/ x)) 1. 100. 1000 "RECIPROCAL") (test (λ(x) x) 0. 5000. 5000000 "IDENTITY") (test (λ(x) x) 0. 6000. 6000000 "IDENTITY")  
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Vlang
Vlang
fn is_pal(ss string) bool { s := ss.runes() for i in 0..s.len/2 { if s[i] != s[s.len-1-i]{ return false } } return true }   fn main() { for word in ["rotor", "rosetta", "step on no pets", "été", "wren", "🦊😀🦊"] { println('$word => ${is_pal(word)}') } }
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Liberty_BASIC
Liberty BASIC
  global outnum$ dim ones$(20),tens$(9),gr$(5),group(5) for a = 0 to 19 read a$:ones$(a)=a$ next a for a = 1 to 8 read a$:tens$(a)=a$ next a   [start] redim gr$(5) redim group(5)   input "Enter a number (nonzero positive integers only less than 1 quadrillion, no commas): ";num$   num$=trim$(num$) numVal=int(val(num$)) if numVal=0 or numVal>999999999999999 then print "Ended" : end   numParse = numVal numLen = len(str$(numParse))   if numLen<=15 then groupCount=5 if numLen<=12 then groupCount=4 if numLen<=9 then groupCount=3 if numLen<=6 then groupCount=2 if numLen<=3 then groupCount=1   if numLen>12 and numLen<=15 then group(5)=int(numParse/1000000000000) call convert group(5)," trillion" gr$(5)=outnum$ numParse=nP(numParse,12) numLen=len(str$(numParse)) end if   if numLen>9 and numLen<=12 then group(4)=int(numParse/1000000000) call convert group(4)," billion" gr$(4)=outnum$ numParse=nP(numParse,9) numLen=len(str$(numParse)) end if   if numLen>6 and numLen<=9 then group(3)=int(numParse/1000000) call convert group(3)," million" gr$(3)=outnum$ numParse=nP(numParse,6) numLen=len(str$(numParse)) end if   if numLen>3 and numLen<=6 then group(2)=int(numParse/1000) call convert group(2)," thousand" gr$(2)=outnum$ numParse=nP(numParse,3) numLen=len(str$(numParse)) end if   if numLen<=3 then group(1)=numParse call convert group(1),"" gr$(1)=outnum$ numLen=len(str$(numParse)) end if   print for a=groupCount to 1 step -1 print gr$(a);" "; next a print print   goto [start]   sub convert num, dem$ outnum$="" for a=len(str$(num)) to 1 step -1 b$=mid$(str$(num),a,1) c=val(b$) d=len(str$(num))-a+1 select case case d=1 outnum$=ones$(c) case d=2 if c<2 then outnum$=ones$(val(right$(str$(num),2))) else if c>=2 and val(right$(str$(num),1))<>0 then outnum$=tens$(c-1)+"-"+outnum$ else outnum$=tens$(c-1) end if end if case d=3 if c<>0 then outnum$=ones$(c)+" hundred "+outnum$ end select next a outnum$=outnum$+dem$ end sub   function nP(num,L) nP=val(right$(str$(num),L)) end function   data "","one","two","three","four","five","six","seven","eight","nine" data "ten","eleven","twelve","thirteen","fourteen","fifteen","sixteen","seventeen","eighteen","nineteen" data "twenty","thirty","forty","fifty","sixty","seventy","eighty","ninety"  
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Julia
Julia
# v0.6   function numrevgame() l = collect(1:9) while issorted(l) shuffle!(l) end score = 0 println("# Number reversal game") while !issorted(l) print("$l\nInsert the index up to which to revert: ") n = parse(Int, readline()) reverse!(l, 1, n) score += 1 end println("$l... You won!\nScore: $score") return score end   numrevgame()
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Python
Python
x = None if x is None: print "x is None" else: print "x is not None"
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#R
R
is.null(NULL) # TRUE is.null(123) # FALSE is.null(NA) # FALSE 123==NULL # Empty logical value, with a warning foo <- function(){} # function that does nothing foo() # returns NULL
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Pascal
Pascal
program Test; {$IFDEF FPC}{$MODE DELPHI}{$ELSE}{$APPTYPE}{$ENDIF} uses sysutils; const cCHAR: array[0..1] of char = ('_','#'); type TRow = array of byte;   function ConvertToRow(const s:string):tRow; var i : NativeInt; Begin i := length(s); setlength(Result,length(s)); For i := i downto 0 do result[i-1]:= ORD(s[i]=cChar[1]); end;   function OutRow(const row:tRow):string; //create output string var i: NativeInt; Begin i := length(row); setlength(result,i); For i := i downto 1 do result[i]:= cChar[row[i-1]]; end;   procedure NextRow(row:pByteArray;MaxIdx:NativeInt); //compute next row in place by the using a small storage for the //2 values, that would otherwise be overridden var leftValue,Value: NativeInt; i,trpCnt: NativeInt; Begin leftValue := 0; trpCnt := row[0]+row[1];   i := 0; while i < MaxIdx do Begin Value := row[i]; //the rule for survive : PopCnt == 2 row[i] := ORD(trpCnt= 2); //reduce popcnt of element before dec(trpCnt,leftValue); //goto next element inc(i); leftValue := Value; //increment popcnt by right element inc(trpCnt,row[i+1]); //move to next position in ring buffer end; row[MaxIdx] := ORD(trpCnt= 2); end;   const TestString: string=' ### ## # # # # # '; var s: string; row:tRow; i: NativeInt; begin s := Teststring; row:= ConvertToRow(s); For i := 0 to 9 do Begin writeln(OutRow(row)); NextRow(@row[0],High(row)); end; end.
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Raku
Raku
use MONKEY-SEE-NO-EVAL;   sub leftrect(&f, $a, $b, $n) { my $h = ($b - $a) / $n; my $end = $b-$h; my $sum = 0; loop (my $i = $a; $i <= $end; $i += $h) { $sum += f($i) } $h * $sum; }   sub rightrect(&f, $a, $b, $n) { my $h = ($b - $a) / $n; my $sum = 0; loop (my $i = $a+$h; $i <= $b; $i += $h) { $sum += f($i) } $h * $sum; }   sub midrect(&f, $a, $b, $n) { my $h = ($b - $a) / $n; my $sum = 0; my ($start, $end) = $a+$h/2, $b-$h/2; loop (my $i = $start; $i <= $end; $i += $h) { $sum += f($i) } $h * $sum; }   sub trapez(&f, $a, $b, $n) { my $h = ($b - $a) / $n; my $partial-sum = 0; my ($start, $end) = $a+$h, $b-$h; loop (my $i = $start; $i <= $end; $i += $h) { $partial-sum += f($i) * 2 } $h / 2 * ( f($a) + f($b) + $partial-sum ); }   sub simpsons(&f, $a, $b, $n) { my $h = ($b - $a) / $n; my $h2 = $h/2; my ($start, $end) = $a+$h, $b-$h; my $sum1 = f($a + $h2); my $sum2 = 0; loop (my $i = $start; $i <= $end; $i += $h) { $sum1 += f($i + $h2); $sum2 += f($i); } ($h / 6) * (f($a) + f($b) + 4*$sum1 + 2*$sum2); }   sub integrate($f, $a, $b, $n, $exact) { my $e = 0.000001; my $r0 = "$f\n in [$a..$b] / $n\n" ~ ' exact result: '~ $exact.round($e);   my ($r1,$r2,$r3,$r4,$r5); my &f; EVAL "&f = $f"; my $p1 = Promise.start( { $r1 = ' rectangle method left: '~ leftrect(&f, $a, $b, $n).round($e) } ); my $p2 = Promise.start( { $r2 = ' rectangle method right: '~ rightrect(&f, $a, $b, $n).round($e) } ); my $p3 = Promise.start( { $r3 = ' rectangle method mid: '~ midrect(&f, $a, $b, $n).round($e) } ); my $p4 = Promise.start( { $r4 = 'composite trapezoidal rule: '~ trapez(&f, $a, $b, $n).round($e) } ); my $p5 = Promise.start( { $r5 = ' quadratic simpsons rule: '~ simpsons(&f, $a, $b, $n).round($e) } );   await $p1, $p2, $p3, $p4, $p5; $r0, $r1, $r2, $r3, $r4, $r5; }   .say for integrate '{ $_ ** 3 }', 0, 1, 100, 0.25; say ''; .say for integrate '1 / *', 1, 100, 1000, log(100); say ''; .say for integrate '*.self', 0, 5_000, 5_000_000, 12_500_000; say ''; .say for integrate '*.self', 0, 6_000, 6_000_000, 18_000_000;
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Wortel
Wortel
@let {  ; Using a hook pal1 @(= @rev)  ; Function with argument pal2 &s = s @rev s  ; for inexact palindromes pal3 ^(@(= @rev) .toLowerCase. &\@replace[&"\s+"g ""]) [[  !pal1 "abcba"  !pal2 "abcbac"  !pal3 "In girum imus nocte et consumimur igni" ]] }
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Logo
Logo
make "numbers {one two three four five six seven eight nine ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen}   make "tens {twenty thirty forty fifty sixty seventy eighty ninety}@2   make "thou [[] thousand million billion trillion] ; expand as desired   to to.english.thou :n :thou if :n = 0 [output []] if :n < 20 [output sentence item :n :numbers first :thou] if :n < 100 [output (sentence item int :n/10 :tens to.english.thou modulo :n 10 [[]] first :thou)] if :n < 1000 [output (sentence item int :n/100 :numbers "hundred to.english.thou modulo :n 100 [[]] first :thou)] output (sentence to.english.thou int :n/1000 butfirst :thou to.english.thou modulo :n 1000 :thou) end   to to.english :n if :n = 0 [output "zero] if :n > 0 [output to.english.thou :n :thou] [output sentence "negative to.english.thou minus :n :thou] end   print to.english 1234567  ; one million two hundred thirty four thousand five hundred sixty seven
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Kotlin
Kotlin
// version 1.1.2   fun isAscending(a: IntArray): Boolean { for (i in 0..8) if (a[i] != i + 1) return false return true }   fun main(args: Array<String>) { val r = java.util.Random() var count = 0 val numbers = IntArray(9) numbers[0] = 2 + r.nextInt(8) // this will ensure list isn't ascending for (i in 1..8) { var rn: Int do { rn = 1 + r.nextInt(9) } while (rn in numbers) numbers[i] = rn } println("Here's your first list : ${numbers.joinToString()}") while (true) { var rev: Int do { print("How many numbers from the left are to be reversed : ") rev = readLine()!!.toInt() } while (rev !in 2..9) count++ var i = 0 var j = rev - 1 while (i < j) { val temp = numbers[i] numbers[i++] = numbers[j] numbers[j--] = temp } if (isAscending(numbers)) { println("Here's your final list : ${numbers.joinToString()}") break } println("Here's your list now  : ${numbers.joinToString()}") } println("So you've completed the game with a score of $count") }
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Racket
Racket
  -> null '() -> (null? null) #t -> (null? 3) #f  
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Raku
Raku
my $var; say $var.WHAT; # Any() $var = 42; say $var.WHAT; # Int() say $var.defined; # True $var = Nil; say $var.WHAT; # Any() say $var.defined # False
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Perl
Perl
  $_="_###_##_#_#_#_#__#__\n"; do { y/01/_#/; print; y/_#/01/; s/(?<=(.))(.)(?=(.))/$1 == $3 ? $1 ? 1-$2 : 0 : $2/eg; } while ($x ne $_ and $x=$_);  
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#REXX
REXX
/*REXX pgm performs numerical integration using 5 different algorithms and show results.*/ numeric digits 20 /*use twenty decimal digits precision. */   do test=1 for 4; say /*perform the 4 different test suites. */ if test==1 then do; L= 0; H= 1; i= 100; end if test==2 then do; L= 1; H= 100; i= 1000; end if test==3 then do; L= 0; H= 5000; i= 5000000; end if test==4 then do; L= 0; H= 6000; i= 6000000; end say center('test' test, 79, "═") /*display a header for the test suite. */ say ' left rectangular('L", "H', 'i") ──► " left_rect(L, H, i) say ' midpoint rectangular('L", "H', 'i") ──► " midpoint_rect(L, H, i) say ' right rectangular('L", "H', 'i") ──► " right_rect(L, H, i) say ' Simpson('L", "H', 'i") ──► " Simpson(L, H, i) say ' trapezium('L", "H', 'i") ──► " trapezium(L, H, i) end /*test*/ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ f: parse arg y; if test>2 then return y /*choose the "as─is" function. */ if test==1 then return y**3 /* " " cube function. */ return 1/y /* " " reciprocal " */ /*──────────────────────────────────────────────────────────────────────────────────────*/ left_rect: procedure expose test; parse arg a,b,#; $= 0; h= (b-a)/# do x=a by h for #; $= $ + f(x) end /*x*/ return $*h/1 /*──────────────────────────────────────────────────────────────────────────────────────*/ midpoint_rect: procedure expose test; parse arg a,b,#; $= 0; h= (b-a)/# do x=a+h/2 by h for #; $= $ + f(x) end /*x*/ return $*h/1 /*──────────────────────────────────────────────────────────────────────────────────────*/ right_rect: procedure expose test; parse arg a,b,#; $= 0; h= (b-a)/# do x=a+h by h for #; $= $ + f(x) end /*x*/ return $*h/1 /*──────────────────────────────────────────────────────────────────────────────────────*/ Simpson: procedure expose test; parse arg a,b,#; h= (b-a)/# hh= h/2; $= f(a + hh) @= 0; do x=1 for #-1; hx=h*x + a; @= @ + f(hx) $= $ + f(hx + hh) end /*x*/   return h * (f(a) + f(b) + 4*$ + 2*@) / 6 /*──────────────────────────────────────────────────────────────────────────────────────*/ trapezium: procedure expose test; parse arg a,b,#; $= 0; h= (b-a)/# do x=a by h for #; $= $ + (f(x) + f(x+h)) end /*x*/ return $*h/2
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Wren
Wren
var isPal = Fn.new { |word| word == ((word.count > 0) ? word[-1..0] : "") }   System.print("Are the following palindromes?") for (word in ["rotor", "rosetta", "step on no pets", "été", "wren", "🦊😀🦊"]) { System.print("  %(word) => %(isPal.call(word))") }
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Lua
Lua
words = {"one ", "two ", "three ", "four ", "five ", "six ", "seven ", "eight ", "nine "} levels = {"thousand ", "million ", "billion ", "trillion ", "quadrillion ", "quintillion ", "sextillion ", "septillion ", "octillion ", [0] = ""} iwords = {"ten ", "twenty ", "thirty ", "forty ", "fifty ", "sixty ", "seventy ", "eighty ", "ninety "} twords = {"eleven ", "twelve ", "thirteen ", "fourteen ", "fifteen ", "sixteen ", "seventeen ", "eighteen ", "nineteen "}   function digits(n) local i, ret = -1 return function() i, ret = i + 1, n % 10 if n > 0 then n = math.floor(n / 10) return i, ret end end end   level = false function getname(pos, dig) --stateful, but effective. level = level or pos % 3 == 0 if(dig == 0) then return "" end local name = (pos % 3 == 1 and iwords[dig] or words[dig]) .. (pos % 3 == 2 and "hundred " or "") if(level) then name, level = name .. levels[math.floor(pos / 3)], false end return name end   local val, vword = io.read() + 0, ""   for i, v in digits(val) do vword = getname(i, v) .. vword end   for i, v in ipairs(words) do vword = vword:gsub("ty " .. v, "ty-" .. v) vword = vword:gsub("ten " .. v, twords[i]) end   if #vword == 0 then print "zero" else print(vword) end
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Lua
Lua
-- Initialisation math.randomseed(os.time()) numList = {values = {}}   -- Check whether list contains n function numList:contains (n) for k, v in pairs(self.values) do if v == n then return true end end return false end   -- Check whether list is in order function numList:inOrder () for k, v in pairs(self.values) do if k ~=v then return false end end return true end   -- Create necessarily out-of-order list function numList:build () local newNum repeat for i = 1, 9 do repeat newNum = math.random(1, 9) until not numList:contains(newNum) table.insert(self.values, newNum) end until not numList:inOrder() end   -- Display list of numbers on one line function numList:show () for k, v in pairs(self.values) do io.write(v .. " ") end io.write(":\t") end   -- Reverse n values from left function numList:reverse (n) local swapList = {} for k, v in pairs(self.values) do table.insert(swapList, v) end for i = 1, n do swapList[i] = self.values[n + 1 - i] end self.values = swapList end   -- Main procedure local score = 0 print("\nRosetta Code Number Reversal Game in Lua") print("========================================\n") numList:build() repeat numList:show() numList:reverse(tonumber(io.read())) score = score + 1 until numList:inOrder() numList:show() print("\n\nW00t! You scored:", score)
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Raven
Raven
NULL as $v $v NULL = # TRUE $v NULL != # FALSE   1 NULL = # FALSE 1.1 NULL = # FALSE   NULL as $v2 $v2 $v = # TRUE
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#REBOL
REBOL
x: none   print ["x" either none? x ["is"]["isn't"] "none."]
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Phix
Phix
string s = "_###_##_#_#_#_#__#__" integer prev='_', curr, toggled = 1 while 1 do ?s for i=2 to length(s)-1 do curr = s[i] if prev=s[i+1] and (curr='#' or prev='#') then s[i] = 130-curr toggled = 1 end if prev = curr end for if not toggled then ?s exit end if toggled = 0 end while
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Ring
Ring
  # Project : Numerical integration   decimals(8) data = [["pow(x,3)",0,1,100], ["1/x",1, 100,1000], ["x",0,5000,5000000], ["x",0,6000,6000000]] see "Function Range L-Rect R-Rect M-Rect Trapeze Simpson" + nl for p = 1 to 4 d1 = data[p][1] d2 = data[p][2] d3 = data[p][3] d4 = data[p][4] see "" + d1 + " " + d2 + " - " + d3 + " " + lrect(d1, d2, d3, d4) + " " + rrect(d1, d2, d3, d4) see " " + mrect(d1, d2, d3, d4) + " " + trapeze(d1, d2, d3, d4) + " " + simpson(d1, d2, d3, d4) + nl next   func lrect(x2, a, b, n) s = 0 d = (b - a) / n x = a for i = 1 to n eval("result = " + x2) s = s + d * result x = x + d next return s   func rrect(x2, a, b, n) s = 0 d = (b - a) / n x = a for i = 1 to n x = x + d eval("result = " + x2) s = s + d *result next return s   func mrect(x2, a, b, n) s = 0 d = (b - a) / n x = a for i = 1 to n x = x + d/2 eval("result = " + x2) s = s + d * result x = x +d/2 next return s   func trapeze(x2, a, b, n) s = 0 d = (b - a) / n x = b eval("result = " + x2) f = result x = a eval("result = " + x2) s = d * (f + result) / 2 for i = 1 to n-1 x = x + d eval("result = " + x2) s = s + d * result next return s   func simpson(x2, a, b, n) s1 = 0 s = 0 d = (b - a) / n x = b eval("result = " + x2) f = result x = a + d/2 eval("result = " + x2) s1 = result for i = 1 to n-1 x = x + d/2 eval("result = " + x2) s = s + result x = x + d/2 eval("result = " + x2) s1 = s1 + result next x = a eval("result = " + x2) return (d / 6) * (f + result + 4 * s1 + 2 * s)  
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#X86_Assembly
X86 Assembly
  ; x86_84 Linux nasm section .text   isPalindrome: mov rsi, rax mov rdi, rax   get_end: cmp byte [rsi], 0 je get_result inc rsi jmp get_end   get_result: mov rax, 0 dec rsi   compare: mov cl, byte [rdi] cmp byte [rsi], cl jne not_palindrome cmp rsi, rdi je palindrome inc rdi cmp rdi, rsi je palindrome dec rsi jmp compare   not_palindrome: mov rax, 0 ret palindrome: mov rax, 1 ret  
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Maple
Maple
number_name := n -> convert(n, english) number_name(2001); "two thousand one"
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#M2000_Interpreter
M2000 Interpreter
  Module Number_Reversal_Game { PRINT "Given a jumbled list of the numbers 1 to 9," PRINT "you must select how many digits from the left to reverse." PRINT "Your goal is to get the digits in order with 1 on the left and 9 on the right." \\ work on a new stack - old stack parked, and attached at the exit of this block Stack New { Data 1,2,3,4,5,6,7,8,9 \\ Create jumbled list For i=1 to 30: Reverse(Random(2,9)):Next i Tries=0 fin=false Repeat { \\ Show Stack Stack Try ok { INPUT " -- How many numbers should be flipped:", flp% } if not Ok then print: Restart if flp%<2 or flp%>9 then Restart Reverse(flp%) Tries++ CheckStack(&fin) } until Fin \\ show stack again Stack PRINT "You took "; tries; " tries to put the digits in order." } Sub Reverse(n) Shift 1, -n ' shift one item nth times in reverse End Sub Sub CheckStack(&ok) ok=true if stack.size<2 then exit sub Local i For i=2 to stack.size { ok=stackitem(i)-stackitem(i-1)=1 if ok else exit } End Sub } Number_Reversal_Game  
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#REXX
REXX
/*REXX program demonstrates null strings, and also undefined values. */   if symbol('ABC')=="VAR" then say 'variable ABC is defined, value='abc"<<<" else say "variable ABC isn't defined." xyz=47 if symbol('XYZ')=="VAR" then say 'variable XYZ is defined, value='xyz"<<<" else say "variable XYZ isn't defined." drop xyz if symbol('XYZ')=="VAR" then say 'variable XYZ is defined, value='xyz"<<<" else say "variable XYZ isn't defined." cat='' if symbol('CAT')=="VAR" then say 'variable CAT is defined, value='cat"<<<" else say "variable CAT isn't defined."
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Ring
Ring
  see isnull(5) + nl + # print 0 isnull("hello") + nl + # print 0 isnull([1,3,5]) + nl + # print 0 isnull("") + nl + # print 1 isnull("NULL") # print 1  
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Phixmonti
Phixmonti
0 1 1 1 0 1 1 0 1 0 1 0 1 0 1 0 0 1 0 0 stklen var w w tolist 0 0 put 0 w 1 + repeat var x2   10 for drop w for var j j get 1 == if "#" else "_" endif print j 1 - get var p1 j get swap j 1 + get rot p1 + + 2 == x2 swap j set var x2 endfor nl drop x2 endfor
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Picat
Picat
go =>  % _ # # # _ # # _ # _ # _ # _ # _ _ # _ _ S = [0,1,1,1,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0], println(init=S), run_ca(S), nl,   println("Some random inits:"), _ = random2(), foreach(N in [5,10,20,50]) S2 = [random() mod 2 : _I in 1..N], run_ca(S2), nl end.   % % Run a CA and show the result. %   % rule/1 is the default run_ca(S) => run_ca(S,rule). run_ca(S,Rules) => Len = S.length, All := [S], Seen = new_map(), % detect fixpoint and cycle while (not Seen.has_key(S)) Seen.put(S,1), T = [S[1]] ++ [apply(Rules, slice(S,I-1,I+1)) : I in 2..Len-1] ++ [S[Len]], All := All ++ [T], S := T end, foreach(A in All) println(A.convert()) end, writeln(len=All.length).   % Convert: % 0->"_" % 1->"#" convert(L) = Res => B = "_#", Res = [B[L[I]+1] : I in 1..L.length].   % the rules rule([0,0,0]) = 0. % rule([0,0,1]) = 0. % rule([0,1,0]) = 0. % Dies without enough neighbours rule([0,1,1]) = 1. % Needs one neighbour to survive rule([1,0,0]) = 0. % rule([1,0,1]) = 1. % Two neighbours giving birth rule([1,1,0]) = 1. % Needs one neighbour to survive rule([1,1,1]) = 0. % Starved to death.
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Ruby
Ruby
def leftrect(f, left, right) f.call(left) end   def midrect(f, left, right) f.call((left+right)/2.0) end   def rightrect(f, left, right) f.call(right) end   def trapezium(f, left, right) (f.call(left) + f.call(right)) / 2.0 end   def simpson(f, left, right) (f.call(left) + 4*f.call((left+right)/2.0) + f.call(right)) / 6.0 end   def integrate(f, a, b, steps, method) delta = 1.0 * (b - a) / steps total = 0.0 steps.times do |i| left = a + i*delta right = left + delta total += delta * send(method, f, left, right) end total end   def square(x) x**2 end   def def_int(f, a, b) l = case f.to_s when /sin>/ lambda {|x| -Math.cos(x)} when /square>/ lambda {|x| (x**3)/3.0} end l.call(b) - l.call(a) end   a = 0 b = Math::PI steps = 10   for func in [method(:square), Math.method(:sin)] puts "integral of #{func} from #{a} to #{b} in #{steps} steps" actual = def_int(func, a, b) for method in [:leftrect, :midrect, :rightrect, :trapezium, :simpson] int = integrate(func, a, b, steps, method) diff = (int - actual) * 100.0 / actual printf "  %-10s  %s\t(%.1f%%)\n", method, int, diff end end
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#XPL0
XPL0
include c:\cxpl\codes; \intrinsic 'code' declarations string 0; \use zero-terminated strings   func StrLen(Str); \Return number of characters in an ASCIIZ string char Str; int I; for I:= 0 to -1>>1-1 do if Str(I) = 0 then return I;   func Palindrome(S); \Return 'true' if S is a palindrome char S; int L, I; [L:= StrLen(S); for I:= 0 to L/2-1 do if S(I) # S(L-1-I) then return false; return true; ]; \Palindrome   int Word, I; [Word:= ["otto", "mary", "ablewasiereisawelba", "ingirumimusnocteetconsumimurigni"]; for I:= 0 to 4-1 do [Text(0, if Palindrome(Word(I)) then "yes" else "no"); CrLf(0); ]; ]
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
small = "zero"["one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen"]; tens = # <> "-" & /@ {"twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety"}; big = Prepend[ " " <> # & /@ {"thousand", "million", "billion", "trillion", "quadrillion", "quintillion", "sextillion", "septillion", "octillion", "nonillion", "decillion", "undecillion", "duodecillion", "tredecillion"}, ""]; name[n_Integer] := "negative " <> name[-n] /; n < 0; name[n_Integer] := small[[n]] /; 0 <= n < 20; name[n_Integer] := StringTrim[tens[[#1 - 1]] <> small[[#2]] & @@ IntegerDigits[n], "-zero"] /; 10 <= n < 100; name[n_Integer] := StringTrim[ small[[#1]] <> " hundred and " <> name@#2 & @@ IntegerDigits[n, 100], " and zero"] /; 100 <= n < 1000; name[n_Integer] := StringJoin@ Riffle[Select[ MapThread[StringJoin, {name /@ #, Reverse@big[[;; Length@#]]}] &@ IntegerDigits[n, 1000], StringFreeQ[#, "zero"] &], ","];
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
Module[{array = Range@9, score = 0}, While[array == Range@9, array = RandomSample@Range@9]; While[array != Range@9, Print@array; (array[[;; #]] = Reverse@array[[;; #]]) &@ Input["How many digits would you like to reverse?"]; score++]; Print@array; Print["Your score:", score]]
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Ruby
Ruby
puts "@object is nil" if @object.nil? # instance variable   puts "$object is nil" if $object.nil? # global variable, too   # It recognizes as the local variable even if it isn't executed. object = 1 if false puts "object is nil" if object.nil?   # nil itself is an object: puts nil.class # => NilClass
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Rust
Rust
// If an option may return null - or nothing - in Rust, it's wrapped // in an Optional which may return either the type of object specified // in <> or None. We can check this using .is_some() and .is_none() on // the Option.   fn check_number(num: &Option<u8>) { if num.is_none() { println!("Number is: None"); } else { println!("Number is: {}", num.unwrap()); } }   fn main() { let mut possible_number: Option<u8> = None; check_number(&possible_number);   possible_number = Some(31); check_number(&possible_number); }
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#PicoLisp
PicoLisp
(let Cells (chop "_###_##_#_#_#_#__#__") (do 10 (prinl Cells) (setq Cells (make (link "_") (map '((L) (case (head 3 L) (`(mapcar chop '("___" "__#" "_#_" "#__" "###")) (link "_") ) (`(mapcar chop '("_##" "#_#" "##_")) (link "#") ) ) ) Cells ) (link "_") ) ) ) )
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Prolog
Prolog
one_dimensional_cellular_automata(L) :- maplist(my_write, L), nl, length(L, N), length(LN, N), % there is a 0 before the beginning compute_next([0 |L], LN), ( L \= LN -> one_dimensional_cellular_automata(LN); true).   % All the possibilites compute_next([0, 0, 0 | R], [0 | R1]) :- compute_next([0, 0 | R], R1).   compute_next([0, 0, 1 | R], [0 | R1]) :- compute_next([0, 1 | R], R1).   compute_next([0, 1, 0 | R], [0 | R1]) :- compute_next([1, 0 | R], R1).   compute_next([0, 1, 1 | R], [1 | R1]) :- compute_next([1, 1 | R], R1).   compute_next([1, 0, 0 | R], [0 | R1]) :- compute_next([0, 0 | R], R1).   compute_next([1, 0, 1 | R], [1 | R1]) :- compute_next([0, 1 | R], R1).   compute_next([1, 1, 0 | R], [1 | R1]) :- compute_next([1, 0 | R], R1).   compute_next([1, 1, 1 | R], [0 | R1]) :- compute_next([1, 1 | R], R1).   % the last four possibilies => % we consider that there is à 0 after the end complang jq># The 1-d cellular automaton: def next: # Conveniently, jq treats null as 0 when it comes to addition # so there is no need to fiddle with the boundaries . as $old | reduce range(0; length) as $i ([]; ($old[$i-1] + $old[$i+1]) as $s | if $s == 0 then .[$i] = 0 elif $s == 1 then .[$i] = (if $old[$i] == 1 then 1 else 0 end) else .[$i] = (if $old[$i] == 1 then 0 else 1 end) end);     # pretty-print an array: def pp: reduce .[] as $i (""; . + (if $i == 0 then " " else "*" end));   # continue until quiescence: def go: recurse(. as $prev | next | if . == $prev then empty else . end) | pp;   # Example: [0,1,1,1,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0] | goute_next([0, 0], [0]).   compute_next([1, 0], [0]).   compute_next([0, 1], [0]).   compute_next([1, 1], [1]).   my_write(0) :- write(.).   my_write(1) :- write(#).   one_dimensional_cellular_automata :- L = [0,1,1,1,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0], one_dimensional_cellular_automata(L).  
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Rust
Rust
fn integral<F>(f: F, range: std::ops::Range<f64>, n_steps: u32) -> f64 where F: Fn(f64) -> f64 { let step_size = (range.end - range.start)/n_steps as f64;   let mut integral = (f(range.start) + f(range.end))/2.; let mut pos = range.start + step_size; while pos < range.end { integral += f(pos); pos += step_size; } integral * step_size }   fn main() { println!("{}", integral(|x| x.powi(3), 0.0..1.0, 100)); println!("{}", integral(|x| 1.0/x, 1.0..100.0, 1000)); println!("{}", integral(|x| x, 0.0..5000.0, 5_000_000)); println!("{}", integral(|x| x, 0.0..6000.0, 6_000_000)); }
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Yorick
Yorick
func is_palindrome(str) { s = strchar(str)(:-1); return allof(s == s(::-1)); }   func prep_palindrome(str) { s = strchar(strlower(str)); w = where(s >= 'a' & s <= 'z'); return strchar(s(w)); }
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#Maxima
Maxima
  l: [99, 300, 310, 1501, 12609, 512609, 43112609, 77000112609, 2000000000100, 999999999999999999, 0, -99, -1501, -77000112609, -123456789987654321]; map( lambda([n], printf(true, "~20d ~r~%", n, n)), l)$  
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#MATLAB
MATLAB
function NumberReversalGame list = randperm(9); while issorted(list) list = randperm(9); end fprintf('Given a list of numbers, try to put them into ascending order\n') fprintf('by sequentially reversing everything left of a point you choose\n') fprintf('in the array. Try to do it in as few reversals as possible.\n') fprintf('No input will quit the game.\n') fprintf('Position Num:%s\n', sprintf(' %d', 1:length(list))) fprintf('Current List:%s', sprintf(' %d', list)) pivot = 1; nTries = 0; while ~isempty(pivot) && ~issorted(list) pivot = input(' Enter position of reversal limit: '); if pivot list(1:pivot) = list(pivot:-1:1); fprintf('Current List:%s', sprintf(' %d', list)) nTries = nTries+1; end end if issorted(list) fprintf('\nCongratulations! You win! Only %d reversals.\n', nTries) else fprintf('\nPlay again soon!\n') end end
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#S-lang
S-lang
variable foo = NULL; print(foo); if (foo == NULL) print(typeof(foo));  
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Scala
Scala
  scala> Nil res0: scala.collection.immutable.Nil.type = List()   scala> Nil == List() res1: Boolean = true   scala> Null <console>:8: error: not found: value Null Null ^   scala> null res3: Null = null   scala> None res4: None.type = None   scala> Unit res5: Unit.type = object scala.Unit   scala> val a = println() a: Unit = ()  
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#PureBasic
PureBasic
EnableExplicit Dim cG.i(21) Dim nG.i(21) Define.i n, Gen   DataSection Data.i 0,1,1,1,0,1,1,0,1,0,1,0,1,0,1,0,0,1,0,0 EndDataSection For n=1 To 20 Read.i cG(n) Next   OpenConsole() Repeat Print("Generation "+Str(Gen)+": ") For n=1 To 20 Print(Chr(95-cG(n)*60)) Next Gen +1 PrintN("") For n=1 To 20 If (cG(n) And (cG(n-1) XOr cg(n+1))) Or (Not cG(n) And (cG(n-1) And cg(n+1))) nG(n)=1 Else nG(n)=0 EndIf Next CopyArray(nG(), cG()) Until Gen > 9   PrintN("Press any key to exit"): Repeat: Until Inkey() <> ""
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Scala
Scala
object NumericalIntegration { def leftRect(f:Double=>Double, a:Double, b:Double)=f(a) def midRect(f:Double=>Double, a:Double, b:Double)=f((a+b)/2) def rightRect(f:Double=>Double, a:Double, b:Double)=f(b) def trapezoid(f:Double=>Double, a:Double, b:Double)=(f(a)+f(b))/2 def simpson(f:Double=>Double, a:Double, b:Double)=(f(a)+4*f((a+b)/2)+f(b))/6;   def fn1(x:Double)=x*x*x def fn2(x:Double)=1/x def fn3(x:Double)=x   type Method = (Double=>Double, Double, Double) => Double def integrate(f:Double=>Double, a:Double, b:Double, steps:Double, m:Method)={ val delta:Double=(b-a)/steps delta*(a until b by delta).foldLeft(0.0)((s,x) => s+m(f, x, x+delta)) }   def print(f:Double=>Double, a:Double, b:Double, steps:Double)={ println("rectangular left  : %f".format(integrate(f, a, b, steps, leftRect))) println("rectangular middle : %f".format(integrate(f, a, b, steps, midRect))) println("rectangular right  : %f".format(integrate(f, a, b, steps, rightRect))) println("trapezoid  : %f".format(integrate(f, a, b, steps, trapezoid))) println("simpson  : %f".format(integrate(f, a, b, steps, simpson))) }   def main(args: Array[String]): Unit = { print(fn1, 0, 1, 100) println("------") print(fn2, 1, 100, 1000) println("------") print(fn3, 0, 5000, 5000000) println("------") print(fn3, 0, 6000, 6000000) } }
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#zkl
zkl
fcn pali(text){ if (text.len()<2) return(False); text==text.reverse(); } fcn pali2(text){ pali((text - " \t\n.,").toLower()) } // or whatever punctuation is
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#MAXScript
MAXScript
  fn numToEng num = ( num = num as integer -- convert to int local originalNumber = num -- store the initial value, to check if it was negative afterwards   num = abs num -- make positive local numStr = num as string -- store as string to check the length   local nonFirstDigits = (if numStr.count > 3 then ((substring numStr ((if mod numStr.count 3 ==0 then 3 else mod numStr.count 3)+1) -1)) else "0") -- this is the string of the number without the beginning, i.e 123456 will give 456, 12035 will give 2035 local singleDigits = #("One","Two","Three","Four","Five","Six","Seven","Eight","Nine") local ElevenTwenty = #("Eleven","Twelve","Thirteen","Fourteen","Fifteen","Sixteen","Seventeen","Eighteen","Nineteen") local tens = #("Ten","Twenty","Thirty","Forty","Fifty","Sixty","Seventy","Eighty","Ninety") local big = #("Hundred","Thousand","Million","Billion") local ret = "" -- this is the value to be returned   case of ( (num == 0 ): ret += "Zero" -- number is zero (num < 10): ret += singleDigits[num] -- number is not and smaller than 10 (num == 10): ret += tens[1] -- number is 10 (num < 20): ret += elevenTwenty[abs(10-num)] -- number is between 11 and 19 (num <= 90 and mod num 10 == 0): ret += tens[num/10] -- number is >= 20 and <= 90 and is dividable by 10 (num < 100): ret += (numToEng (floor(num/10.0)*10) +" "+ numtoEng (num-(floor(num/10.0))*10)) -- number is >= 20, < 100 and is not dividable by 10 (num < 1000): ret += (singledigits[floor(num/100) as integer] + " "+big[1]+ (if mod num 100 != 0 then (" and "+numtoeng (num-(floor(num/100.0)*100))) else "")) -- number is >= 100, < 1000 (num >= 1000): ret += -- number is >= 1000 ( numtoeng (substring numStr 1 (if mod numStr.count 3 ==0 then 3 else mod numStr.count 3)) + \ " " + big[1+((numStr.count-1)/3)] + (if nonFirstDigits as integer == 0 then "" else (if nonFirstDigits as integer < 100 then " and " else ", ")) + \ (if (mod num 1000 == 0) then "" else (numtoeng nonFirstDigits))   ) )   if originalNumber < 0 and (substring ret 1 8) != "Negative" do ret = ("Negative "+ret) -- if number is negative ret = (toupper ret[1]) + (tolower (substring ret 2 -1)) -- make the first char uppercase and rest lowercase return ret )
http://rosettacode.org/wiki/Number_reversal_game
Number reversal game
Task Given a jumbled list of the numbers   1   to   9   that are definitely   not   in ascending order. Show the list,   and then ask the player how many digits from the left to reverse. Reverse those digits,   then ask again,   until all the digits end up in ascending order. The score is the count of the reversals needed to attain the ascending order. Note: Assume the player's input does not need extra validation. Related tasks   Sorting algorithms/Pancake sort   Pancake sorting.   Topswops
#Nim
Nim
import random, rdstdin, strutils, algorithm randomize()   proc isSorted[T](s: openarray[T]): bool = var last = low(T) for c in s: if c < last: return false last = c return true   proc toString[T](s: openarray[T]): string = result = "" for i, x in s: if i > 0: result.add " " result.add($x)   echo """number reversal game Given a jumbled list of the numbers 1 to 9 Show the list. Ask the player how many digits from the left to reverse. Reverse those digits then ask again. until all the digits end up in ascending order."""   var data = @[1,2,3,4,5,6,7,8,9] var trials = 0 while isSorted data: shuffle data while not isSorted data: inc trials var flip = parseInt readLineFromStdin( "#" & $trials & ": List: '" & toString(data) & "' Flip how many?: ") reverse(data, 0, flip - 1)   echo "You took ", trials, " attempts to put the digits in order!"
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Scheme
Scheme
(null? object)
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Sidef
Sidef
var undefined; # initialized with an implicit nil say undefined==nil; # true say defined(nil) # false
http://rosettacode.org/wiki/Null_object
Null object
Null (or nil) is the computer science concept of an undefined or unbound object. Some languages have an explicit way to access the null object, and some don't. Some languages distinguish the null object from undefined values, and some don't. Task Show how to access null in your language by checking to see if an object is equivalent to the null object. This task is not about whether a variable is defined. The task is about "null"-like values in various languages, which may or may not be related to the defined-ness of variables in your language.
#Slate
Slate
Nil isNil = True.
http://rosettacode.org/wiki/One-dimensional_cellular_automata
One-dimensional cellular automata
Assume an array of cells with an initial distribution of live and dead cells, and imaginary cells off the end of the array having fixed values. Cells in the next generation of the array are calculated based on the value of the cell and its left and right nearest neighbours in the current generation. If, in the following table, a live cell is represented by 1 and a dead cell by 0 then to generate the value of the cell at a particular index in the array of cellular values you use the following table: 000 -> 0 # 001 -> 0 # 010 -> 0 # Dies without enough neighbours 011 -> 1 # Needs one neighbour to survive 100 -> 0 # 101 -> 1 # Two neighbours giving birth 110 -> 1 # Needs one neighbour to survive 111 -> 0 # Starved to death.
#Python
Python
import random   printdead, printlive = '_#' maxgenerations = 10 cellcount = 20 offendvalue = '0'   universe = ''.join(random.choice('01') for i in range(cellcount))   neighbours2newstate = { '000': '0', '001': '0', '010': '0', '011': '1', '100': '0', '101': '1', '110': '1', '111': '0', }   for i in range(maxgenerations): print "Generation %3i:  %s" % ( i, universe.replace('0', printdead).replace('1', printlive) ) universe = offendvalue + universe + offendvalue universe = ''.join(neighbours2newstate[universe[i:i+3]] for i in range(cellcount))
http://rosettacode.org/wiki/Numerical_integration
Numerical integration
Write functions to calculate the definite integral of a function ƒ(x) using all five of the following methods: rectangular left right midpoint trapezium Simpson's composite Your functions should take in the upper and lower bounds (a and b), and the number of approximations to make in that range (n). Assume that your example already has a function that gives values for ƒ(x) . Simpson's method is defined by the following pseudo-code: Pseudocode: Simpson's method, composite procedure quad_simpson_composite(f, a, b, n) h := (b - a) / n sum1 := f(a + h/2) sum2 := 0 loop on i from 1 to (n - 1) sum1 := sum1 + f(a + h * i + h/2) sum2 := sum2 + f(a + h * i)   answer := (h / 6) * (f(a) + f(b) + 4*sum1 + 2*sum2) Demonstrate your function by showing the results for:   ƒ(x) = x3,       where   x   is     [0,1],       with           100 approximations.   The exact result is     0.25               (or 1/4)   ƒ(x) = 1/x,     where   x   is   [1,100],     with        1,000 approximations.   The exact result is     4.605170+     (natural log of 100)   ƒ(x) = x,         where   x   is   [0,5000],   with 5,000,000 approximations.   The exact result is   12,500,000   ƒ(x) = x,         where   x   is   [0,6000],   with 6,000,000 approximations.   The exact result is   18,000,000 See also   Active object for integrating a function of real time.   Special:PrefixIndex/Numerical integration for other integration methods.
#Scheme
Scheme
(define (integrate f a b steps meth) (define h (/ (- b a) steps)) (* h (let loop ((i 0) (s 0)) (if (>= i steps) s (loop (+ i 1) (+ s (meth f (+ a (* h i)) h)))))))   (define (left-rect f x h) (f x)) (define (mid-rect f x h) (f (+ x (/ h 2)))) (define (right-rect f x h) (f (+ x h))) (define (trapezium f x h) (/ (+ (f x) (f (+ x h))) 2)) (define (simpson f x h) (/ (+ (f x) (* 4 (f (+ x (/ h 2)))) (f (+ x h))) 6))   (define (square x) (* x x))   (define rl (integrate square 0 1 10 left-rect)) (define rm (integrate square 0 1 10 mid-rect)) (define rr (integrate square 0 1 10 right-rect)) (define t (integrate square 0 1 10 trapezium)) (define s (integrate square 0 1 10 simpson))
http://rosettacode.org/wiki/Palindrome_detection
Palindrome detection
A palindrome is a phrase which reads the same backward and forward. Task[edit] Write a function or program that checks whether a given sequence of characters (or, if you prefer, bytes) is a palindrome. For extra credit: Support Unicode characters. Write a second function (possibly as a wrapper to the first) which detects inexact palindromes, i.e. phrases that are palindromes if white-space and punctuation is ignored and case-insensitive comparison is used. Hints It might be useful for this task to know how to reverse a string. This task's entries might also form the subjects of the task Test a function. Related tasks Word plays Ordered words Palindrome detection Semordnilap Anagrams Anagrams/Deranged anagrams Other tasks related to string operations: Metrics Array length String length Copy a string Empty string  (assignment) Counting Word frequency Letter frequency Jewels and stones I before E except after C Bioinformatics/base count Count occurrences of a substring Count how many vowels and consonants occur in a string Remove/replace XXXX redacted Conjugate a Latin verb Remove vowels from a string String interpolation (included) Strip block comments Strip comments from a string Strip a set of characters from a string Strip whitespace from a string -- top and tail Strip control codes and extended characters from a string Anagrams/Derangements/shuffling Word wheel ABC problem Sattolo cycle Knuth shuffle Ordered words Superpermutation minimisation Textonyms (using a phone text pad) Anagrams Anagrams/Deranged anagrams Permutations/Derangements Find/Search/Determine ABC words Odd words Word ladder Semordnilap Word search Wordiff  (game) String matching Tea cup rim text Alternade words Changeable words State name puzzle String comparison Unique characters Unique characters in each string Extract file extension Levenshtein distance Palindrome detection Common list elements Longest common suffix Longest common prefix Compare a list of strings Longest common substring Find common directory path Words from neighbour ones Change e letters to i in words Non-continuous subsequences Longest common subsequence Longest palindromic substrings Longest increasing subsequence Words containing "the" substring Sum of the digits of n is substring of n Determine if a string is numeric Determine if a string is collapsible Determine if a string is squeezable Determine if a string has all unique characters Determine if a string has all the same characters Longest substrings without repeating characters Find words which contains all the vowels Find words which contains most consonants Find words which contains more than 3 vowels Find words which first and last three letters are equals Find words which odd letters are consonants and even letters are vowels or vice_versa Formatting Substring Rep-string Word wrap String case Align columns Literals/String Repeat a string Brace expansion Brace expansion using ranges Reverse a string Phrase reversals Comma quibbling Special characters String concatenation Substring/Top and tail Commatizing numbers Reverse words in a string Suffixation of decimal numbers Long literals, with continuations Numerical and alphabetical suffixes Abbreviations, easy Abbreviations, simple Abbreviations, automatic Song lyrics/poems/Mad Libs/phrases Mad Libs Magic 8-ball 99 Bottles of Beer The Name Game (a song) The Old lady swallowed a fly The Twelve Days of Christmas Tokenize Text between Tokenize a string Word break problem Tokenize a string with escaping Split a character string based on change of character Sequences Show ASCII table De Bruijn sequences Self-referential sequences Generate lower case ASCII alphabet
#Zoea
Zoea
  program: palindrome case: 1 input: abcdcba output: true   case: 2 input: dog output: false   case: 3 input: x output: true   case: 4 input: abc output: false  
http://rosettacode.org/wiki/Number_names
Number names
Task Show how to spell out a number in English. You can use a preexisting implementation or roll your own, but you should support inputs up to at least one million (or the maximum value of your language's default bounded integer type, if that's less). Support for inputs other than positive integers (like zero, negative integers, and floating-point numbers) is optional. Related task   Spelling of ordinal numbers.
#MiniScript
MiniScript
singles = " one two three four five six seven eight nine ".split teens = "ten eleven twelve thirteen fourteen fifteen sixteen seventeen eighteen nineteen ".split tys = " twenty thirty forty fifty sixty seventy eighty ninety".split ions = "thousand million billion".split   numberName = function(n) if n == 0 then return "zero" a = abs(n) r = "" // (result) for u in ions h = a % 100 if h > 0 and h < 10 then r = singles[h] + " " + r if h > 9 and h < 20 then r = teens[h-10] + " " + r if h > 19 and h < 100 then r = tys[h/10] + "-"*(h%10>0) + singles[h%10] + " " + r h = floor((a % 1000) / 100) if h then r = singles[h] + " hundred " + r a = floor(a / 1000) if a == 0 then break if a % 1000 > 0 then r = u + " " + r end for if n < 0 then r = "negative " + r return r end function   // Test cases: for n in [-1234, 0, 7, 42, 4325, 1000004, 214837564] print n + ": " + numberName(n) end for