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http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#SNOBOL4
SNOBOL4
* # Define complex datatype data('complex(r,i)')   * # Addition define('addx(x1,x2)a,b,c,d') :(addx_end) addx a = r(x1); b = i(x1); c = r(x2); d = i(x2) addx = complex(a + c, b + d) :(return) addx_end   * # Multiplication define('multx(x1,x2)a,b,c,d') :(multx_...
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#Standard_ML
Standard ML
  (* Signature for complex numbers *) signature COMPLEX = sig type num   val complex : real * real -> num   val negative : num -> num val plus : num -> num -> num val minus : num -> num -> num val times : num -> num -> num val invert : num -> num val print_number : num -> unit end;   (* Actual implementation *)...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Pascal
Pascal
program ZToZ; uses math; begin write('0.0 ^ 0 :',IntPower(0.0,0):4:2); writeln(' 0.0 ^ 0.0 :',Power(0.0,0.0):4:2); end.
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Perl
Perl
print 0 ** 0, "\n";   use Math::Complex;   print cplx(0,0) ** cplx(0,0), "\n";
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#D
D
import std.stdio, std.traits, std.algorithm, std.math;   enum Content { Beer, Coffee, Milk, Tea, Water, Danish, English, German, Norwegian, Swedish, Blue, Green, Red, White, Yellow, Blend, BlueMaster, Dunhill, PallMall, Prince, Bird, Cat, Dog, Horse, Zebra } e...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#E
E
? def xml__quasiParser := <import:org.switchb.e.xml.makeXMLQuasiParser>() > def xpath__quasiParser := xml__quasiParser.xPathQuasiParser() > null   ? def doc := xml`<inventory title="OmniCorp Store #45x10^3"> > <section name="health"> > <item upc="123456789" stock="12"> > <name>Invisibility Cream</name> > ...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#Delphi
Delphi
procedure DrawYinAndYang(Canv: TCanvas; R: TRect); begin Canv.Brush.Color := clWhite; Canv.Pen.Color := clWhite; Canv.Pie(R.Left, R.Top, R.Right, R.Bottom, (R.Right + R.Left) div 2, R.Top, (R.Right + R.Left) div 2, R.Bottom); Canv.Brush.Color := clBlack; Canv.Pen.Color := clBlack; Canv.Pie(R.Left, R.Top...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#CoffeeScript
CoffeeScript
Y = (f) -> g = f( (t...) -> g(t...) )
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#CoffeeScript
CoffeeScript
  # Calculate a zig-zag pattern of numbers like so: # 0 1 5 # 2 4 6 # 3 7 8 # # There are many interesting ways to solve this; we # try for an algebraic approach, calculating triangle # areas, so that me minimize space requirements.   zig_zag_value = (x, y, n) ->   upper_triangle_zig_zag = (x, y) -> # calcu...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#REXX
REXX
/*REXX program calculates any number of terms in the Yellowstone (permutation) sequence.*/ parse arg m . /*obtain optional argument from the CL.*/ if m=='' | m=="," then m= 30 /*Not specified? Then use the default.*/ !.= 0 ...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Ring
Ring
  see "working..." + nl row = 3 num = 2 numbers = 1:51 first = 2 second = 3 see "Yellowstone numbers are:" + nl see "1 " + first + " " + second + " "   for n = 4 to len(numbers) flag1 = 1 flag2 = 1 if first < numbers[n] min = first else min = numbers[n] ...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#Raku
Raku
  use Gumbo; use LWP::Simple; use XML::Text;   class YahooSearch { has $!dom;   submethod BUILD (:$!dom) { }   method new($term) { self.bless( dom => parse-html( LWP::Simple.get("http://search.yahoo.com/search?p={ $term }") ) ); }   method next { $!dom = parse-html( LWP::...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Mathematica_.2F_Wolfram_Language
Mathematica / Wolfram Language
s:=ToString[5^4^3^2]; Print[StringTake[s,20]<>"..."<>StringTake[s,-20]<>" ("<>ToString@StringLength@s<>" digits)"];
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#MATLAB
MATLAB
>> answer = vpi(5)^(vpi(4)^(vpi(3)^vpi(2))); >> numDigits = order(answer) + 1   numDigits =   183231   >> [sprintf('%d',leadingdigit(answer,20)) '...' sprintf('%d',trailingdigit(answer,20))] %First and Last 20 Digits   ans =   62060698786608744707...92256259918212890625
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#Pascal
Pascal
  program ZeckendorfRep_RC;   {$mode objfpc}{$H+}   uses SysUtils;   // Return Zeckendorf representation of the passed-in cardinal. function ZeckRep( C : cardinal) : string; var a, b, rem : cardinal; j, nrDigits: integer; begin // Case C = 0 has to be treated specially if (C = 0) then begin result := '0'; ...
http://rosettacode.org/wiki/100_doors
100 doors
There are 100 doors in a row that are all initially closed. You make 100 passes by the doors. The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it). The second time, only visit every 2nd door   (door #2, #4, #6, ...),   and toggle it. The third...
#Common_Lisp
Common Lisp
(defun visit-door (doors doornum value1 value2) "visits a door, swapping the value1 to value2 or vice-versa" (let ((d (copy-list doors)) (n (- doornum 1))) (if (eql (nth n d) value1) (setf (nth n d) value2) (setf (nth n d) value1)) d))   (defun visit-every (doors num iter value1 value...
http://rosettacode.org/wiki/Arrays
Arrays
This task is about arrays. For hashes or associative arrays, please see Creating an Associative Array. For a definition and in-depth discussion of what an array is, see Array. Task Show basic array syntax in your language. Basically, create an array, assign a value to it, and retrieve an element   (if available,...
#Go
Go
package main   import ( "fmt" )   func main() { // creates an array of five ints. // specified length must be a compile-time constant expression. // this allows compiler to do efficient bounds checking. var a [5]int   // since length is compile-time constant, len() is a compile time constant ...
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#Stata
Stata
mata C(2,3) 2 + 3i   a=2+3i b=1-2*i     a+b -5 + 3i   a-b 9 + 3i   a*b -14 - 21i   a/b -.285714286 - .428571429i   -a -2 - 3i   1/a .153846154 - .230769231i   conj(a) 2 - 3i   abs(a) 3.605551275   arg(a) .9827937232   exp(a) -7.31511009 + 1.04274366i   log(a) 1.28247468 + .982793723i   end
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#Swift
Swift
  public struct Complex {   public let real : Double public let imaginary : Double   public init(real inReal:Double, imaginary inImaginary:Double) { real = inReal imaginary = inImaginary }   public static var i : Complex = Complex(real:0, imaginary: 1) public static var zero : Co...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Phix
Phix
?power(0,0) requires("0.8.4") -- (now fixed/crashes on earlier versions) include complex.e complex a = complex_new(0,0), b = complex_power(a,a) string sa = complex_sprint(a,true), sb = complex_sprint(b,true) printf(1,"%s ^ %s = %s\n",{sa,sa,sb})
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Phixmonti
Phixmonti
def mypower dup not if . sign dup 0 == if . 1 endif else power endif enddef   0 0 mypower print
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#EchoLisp
EchoLisp
  (lib 'hash) (lib 'amb)   ;; return #f or house# for thing/category ;; houses := (0 1 2 3 4) (define (house-get H category thing houses) (for/or ((i houses)) #:continue (!equal? (hash-ref (vector-ref H i) category) thing) i))   ;; return house # for thing (eg cat) in category (eq animals) ;; add th...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Erlang
Erlang
  -module(xml_xpath). -include_lib("xmerl/include/xmerl.hrl").   -export([main/0]).   main() -> XMLDocument = "<inventory title=\"OmniCorp Store #45x10^3\"> <section name=\"health\"> <item upc=\"123456789\" stock=\"12\"> <name>Invisibility Cream</name> <price>14.50</...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#DWScript
DWScript
type TColorFuncX = function (x : Integer) : Integer;   type TSquareBoard = class Scale : Integer; Pix : array of array of Integer;   constructor Create(aScale : Integer); begin Scale := aScale; Pix := new Integer[aScale*12+1, aScale*12+1]; end;   method Print;...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#Common_Lisp
Common Lisp
(defun Y (f) ((lambda (g) (funcall g g)) (lambda (g) (funcall f (lambda (&rest a) (apply (funcall g g) a))))))   (defun fac (n) (funcall (Y (lambda (f) (lambda (n) (if (zerop n) 1 (* n (funcall f (1- n))))))) n))   (defun fib (n) (funcall (Y (lambda (f) (lambda ...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#Common_Lisp
Common Lisp
(defun zigzag (n) (flet ((move (i j) (if (< j (1- n)) (values (max 0 (1- i)) (1+ j)) (values (1+ i) j)))) (loop with a = (make-array (list n n) :element-type 'integer) with x = 0 with y = 0 for v from 0 below (* n n) do (setf (aref a...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Ruby
Ruby
def yellow(n) a = [1, 2, 3] b = { 1 => true, 2 => true, 3 => true } i = 4 while n > a.length if !b[i] && i.gcd(a[-1]) == 1 && i.gcd(a[-2]) > 1 a << i b[i] = true i = 4 end i += 1 end a end   p yellow(30)
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Rust
Rust
// [dependencies] // num = "0.3" // plotters = "^0.2.15"   use num::integer::gcd; use plotters::prelude::*; use std::collections::HashSet;   fn yellowstone_sequence() -> impl std::iter::Iterator<Item = u32> { let mut sequence: HashSet<u32> = HashSet::new(); let mut min = 1; let mut n = 0; let mut n1 = 0...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#Ruby
Ruby
require 'open-uri' require 'hpricot'   SearchResult = Struct.new(:url, :title, :content)   class SearchYahoo @@urlinfo = [nil, 'ca.search.yahoo.com', 80, '/search', nil, nil]   def initialize(term) @term = term @page = 1 @results = nil @url = URI::HTTP.build(@@urlinfo) end   def next_result ...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Maxima
Maxima
block([s, n], s: string(5^4^3^2), n: slength(s), print(substring(s, 1, 21), "...", substring(s, n - 19)), n); /* 62060698786608744707...92256259918212890625 183231 */
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Nanoquery
Nanoquery
value = str(5^(4^(3^2)))   first20 = value.substring(0,20) last20 = value.substring(len(value) - 20)   println "The first twenty digits are " + first20 println "The last twenty digits are " + last20   if (first20 = "62060698786608744707") && (last20 = "92256259918212890625") println "\nThese digits are correct.\n" end...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Nemerle
Nemerle
using System.Console; using System.Numerics; using System.Numerics.BigInteger;   module BigInt { Main() : void { def n = Pow(5, Pow(4, Pow(3, 2) :> int) :> int).ToString(); def len = n.Length; def first20 = n.Substring(0, 20); def last20 = n.Substring(len - 20, 20);   ass...
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#Perl
Perl
my @fib;   sub fib { my $n = shift; return 1 if $n < 2; return $fib[$n] //= fib($n-1)+fib($n-2); }   sub zeckendorf { my $n = shift; return "0" unless $n; my $i = 1; $i++ while fib($i) <= $n; my $z = ''; while( --$i ) { $z .= "0", next if fib( $i ) > $n; $z .= "1"; $n -= fib( $i ); } r...
http://rosettacode.org/wiki/100_doors
100 doors
There are 100 doors in a row that are all initially closed. You make 100 passes by the doors. The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it). The second time, only visit every 2nd door   (door #2, #4, #6, ...),   and toggle it. The third...
#Component_Pascal
Component Pascal
  MODULE Doors100; IMPORT StdLog;   PROCEDURE Do*; VAR i,j: INTEGER; closed: ARRAY 101 OF BOOLEAN; BEGIN (* initialization of closed to true *) FOR i := 0 TO LEN(closed) - 1 DO closed[i] := TRUE END; (* process *) FOR i := 1 TO LEN(closed) DO; j := 1; WHILE j < LEN(closed) DO IF j MOD i = 0 THEN closed[j]...
http://rosettacode.org/wiki/Arrays
Arrays
This task is about arrays. For hashes or associative arrays, please see Creating an Associative Array. For a definition and in-depth discussion of what an array is, see Array. Task Show basic array syntax in your language. Basically, create an array, assign a value to it, and retrieve an element   (if available,...
#Golfscript
Golfscript
[1 2 3]:a; # numeric only array, assigned to a and then dropped 10,:a; # assign to a [0 1 2 3 4 5 6 7 8 9] a 0= puts # pick element at index 0 (stack: 0) a 10+puts # append 10 to the end of a 10 a+puts # prepend 10 to a
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#Tcl
Tcl
package require math::complexnumbers namespace import math::complexnumbers::*   set a [complex 1 1] set b [complex 3.14159 1.2] puts [tostring [+ $a $b]] ;# ==> 4.14159+2.2i puts [tostring [* $a $b]] ;# ==> 1.94159+4.34159i puts [tostring [pow $a [complex -1 0]]] ;# ==> 0.5-0.4999999999999999i puts [tostring [- $a]] ;#...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#PHP
PHP
<?php echo pow(0,0); echo 0 ** 0; // PHP 5.6+ only ?>
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#PicoLisp
PicoLisp
  (** 0 0)  
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Pike
Pike
write( pow(0, 0) +"\n" );
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#Elixir
Elixir
defmodule ZebraPuzzle do defp adjacent?(n,i,g,e) do Enum.any?(0..3, fn x -> (Enum.at(n,x)==i and Enum.at(g,x+1)==e) or (Enum.at(n,x+1)==i and Enum.at(g,x)==e) end) end   defp leftof?(n,i,g,e) do Enum.any?(0..3, fn x -> Enum.at(n,x)==i and Enum.at(g,x+1)==e end) end   defp coincident?(n,i,g,e...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#F.23
F#
  open System.IO open System.Xml.XPath   let xml = new StringReader(""" <inventory title="OmniCorp Store #45x10^3"> <section name="health"> <item upc="123456789" stock="12"> <name>Invisibility Cream</name> <price>14.50</price> <description>Makes you invisible</description> </item> <item ...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#F.C5.8Drmul.C3.A6
Fōrmulæ
: circle ( x y r h -- f ) rot - dup * rot dup * + swap dup * swap < invert ;   : pixel ( r x y -- r c ) 2dup 4 pick 6 / 5 pick 2 / negate circle if 2drop '#' exit then 2dup 4 pick 6 / 5 pick 2 / circle if 2drop '.' exit then 2dup 4 pick 2 / 5 pick 2 / negate circle if 2drop '.' exit then 2dup 4 pick 2 / 5 pic...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#Forth
Forth
: circle ( x y r h -- f ) rot - dup * rot dup * + swap dup * swap < invert ;   : pixel ( r x y -- r c ) 2dup 4 pick 6 / 5 pick 2 / negate circle if 2drop '#' exit then 2dup 4 pick 6 / 5 pick 2 / circle if 2drop '.' exit then 2dup 4 pick 2 / 5 pick 2 / negate circle if 2drop '.' exit then 2dup 4 pick 2 / 5 pic...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#Crystal
Crystal
require "big"   struct RecursiveFunc(T) # a generic recursive function wrapper... getter recfnc : RecursiveFunc(T) -> T def initialize(@recfnc) end end   struct YCombo(T) # a struct or class needs to be used so as to be generic... def initialize (@fnc : Proc(T) -> T) end def fixy g = -> (x : RecursiveFunc(T...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#Crystal
Crystal
def zigzag(n) (seq=(0...n).to_a).product(seq) .sort_by {|x,y| [x+y, (x+y).even? ? y : -y]} .map_with_index{|v, i| {v, i}}.sort.map(&.last).each_slice(n).to_a end   def print_matrix(m) format = "%#{m.flatten.max.to_s.size}d " * m[0].size m.each {|row| puts format % row} end   print_matrix zigzag(5)
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Tcl
Tcl
proc gcd {a b} { while {$b} { lassign [list $b [expr {$a % $b}]] a b } return $a }   proc gen_yellowstones {{maxN 30}} { set r {} for {set n 1} {$n <= $maxN} {incr n} { if {$n <= 3} { lappend r $n } else { ## NB: list indices start at 0, not 1. ...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#Run_BASIC
Run BASIC
'-------------------------------------------------------------------------- ' send this from the server to the clients browser '-------------------------------------------------------------------------- html "<table border=1 cellpadding=0 cellspacing=0 bgcolor=wheat>" html "<tr><td align=center colspan=2>Yahoo Search</...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#Tcl
Tcl
package require http   proc fix s { string map {<b>...</b> "" <b> "" </b> "" <wbr> "" "<wbr />" ""} \ [regsub "</a></h3></div>.*" $s ""] } proc YahooSearch {term {page 1}} { # Build the (ugly) scraper URL append re {<a class="yschttl spt" href=".+?" >(.+?)</a></h3>} append re {</div><div cla...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#NewLisp
NewLisp
  ;;; No built-in big integer exponentiation (define (exp-big x n) (setq x (bigint x)) (let (y 1L) (if (= n 0) 1L (while (> n 1) (if (odd? n) (setq y (* x y))) (setq x (* x x) n (/ n 2))) (* x y)))) ; ;;; task (define (test) (local (res) ; drop the "L" at the end (setq res (0 (- (length re...
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#Phix
Phix
function zeckendorf(integer n) integer r = 0, c sequence fib = {1,1} while fib[$]<n do fib &= fib[$] + fib[$-1] end while for i=length(fib) to 2 by -1 do c = n>=fib[i] r += r+c n -= c*fib[i] end for return r end function for i=0 to 20 do printf(1,"%2d: %7b\n",{i...
http://rosettacode.org/wiki/100_doors
100 doors
There are 100 doors in a row that are all initially closed. You make 100 passes by the doors. The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it). The second time, only visit every 2nd door   (door #2, #4, #6, ...),   and toggle it. The third...
#Coq
Coq
Require Import List.   Fixpoint rep {A} (a : A) n := match n with | O => nil | S n' => a::(rep a n') end.   Fixpoint flip (l : list bool) (n k : nat) : list bool := match l with | nil => nil | cons h t => match k with | O => (negb h) :: (flip t n n) | S k' => h :: (...
http://rosettacode.org/wiki/Arrays
Arrays
This task is about arrays. For hashes or associative arrays, please see Creating an Associative Array. For a definition and in-depth discussion of what an array is, see Array. Task Show basic array syntax in your language. Basically, create an array, assign a value to it, and retrieve an element   (if available,...
#Groovy
Groovy
def aa = [ 1, 25, 31, -3 ] // list def a = [0] * 100 // list of 100 zeroes def b = 1..9 // range notation def c = (1..10).collect { 2.0**it } // each output element is 2**(corresponding invoking list element)   // There are no true "multi-dimensional" arrays in Groo...
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#TI-83_BASIC
TI-83 BASIC
■ √(–1)  ■ ^2 —1 ■  + 1 1 +  ■ (1+) * 2 2 + 2* ■ (1+) (2) —2 + 2* ■ —(1+) —1 -  ■ 1/(2) —1 -  ■ real(1 + 2) 1 ■ imag(1 + 2) 2
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#TI-89_BASIC
TI-89 BASIC
■ √(–1)  ■ ^2 —1 ■  + 1 1 +  ■ (1+) * 2 2 + 2* ■ (1+) (2) —2 + 2* ■ —(1+) —1 -  ■ 1/(2) —1 -  ■ real(1 + 2) 1 ■ imag(1 + 2) 2
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#PL.2FI
PL/I
zhz: Proc Options(Main); Dcl a dec float(10) Init(1); Dcl b dec float(10) Init(0); Put skip list('1**0=',a**b); Put skip list('0**1=',b**a); Put skip list('0**0=',b**b); End;
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Plain_English
Plain English
To run: Start up. Put 0 into a number. Raise the number to 0. Convert the number to a string. Write the string to the console. Wait for the escape key. Shut down.
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#Erlang
Erlang
  -module( zebra_puzzle ).   -export( [task/0] ).   -record( house, {colour, drink, nationality, number, pet, smoke} ). -record( sorted_houses, {house_1s=[], house_2s=[], house_3s=[], house_4s=[], house_5s=[]} ).   task() -> Houses = [#house{colour=C, drink=D, nationality=N, number=Nr, pet=P, smoke=S} || C <- all_colo...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Factor
Factor
    ! Get first item element """<inventory title="OmniCorp Store #45x10^3"> <section name="health"> <item upc="123456789" stock="12"> <name>Invisibility Cream</name> <price>14.50</price> <description>Makes you invisible</description> </item> <item upc="445322344" stock="18"> <name>...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Gastona
Gastona
#javaj#   <frames> oSal, XML Path sample, 300, 400   #data#   <xml> //<inventory title="OmniCorp Store #45x10^3"> // <section name="health"> // <item upc="123456789" stock="12"> // <name>Invisibility Cream</name> // <price>14.50</price> // <description>Makes ...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#Go
Go
package main   import ( "fmt" "os" "text/template" )   var tmpl = `<?xml version="1.0"?> <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" width="210" height="150"> <symbol id="yy" viewBox="0 0 200 200"> <circle stroke="black" stroke-width="2" fill="white" cx="10...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#D
D
import std.stdio, std.traits, std.algorithm, std.range;   auto Y(S, T...)(S delegate(T) delegate(S delegate(T)) f) { static struct F { S delegate(T) delegate(F) f; alias f this; } return (x => x(x))(F(x => f((T v) => x(x)(v)))); }   void main() { // Demo code: auto factorial = Y((int del...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#D
D
int[][] zigZag(in int n) pure nothrow @safe { static void move(in int n, ref int i, ref int j) pure nothrow @safe @nogc { if (j < n - 1) { if (i > 0) i--; j++; } else i++; }   auto a = new int[][](n, n); int x, y; foreach (v; 0 .. n ^^ 2) { ...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#uBasic.2F4tH
uBasic/4tH
Dim @y(30)   @y(0) = 1 @y(1) = 2 @y(2) = 3   For i = 3 To 29 k = 3 Do k = k + 1 If (FUNC(_gcd(k, @y(i-2))) = 1) + (FUNC(_gcd(k, @y(i-1))) > 1) Then Continue EndIf   For j = 0 To i - 1 If @y(j) = k Then Unloop : Continue Next   @y(i) = k : Break Loop Next   For i = 0 To 29 Pri...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#VBA
VBA
  Function gcd(a As Long, b As Long) As Long If b = 0 Then gcd = a Exit Function End If gcd = gcd(b, a Mod b) End Function   Sub Yellowstone() Dim i As Long, j As Long, k As Long, Y(1 To 30) As Long   Y(1) = 1 Y(2) = 2 Y(3) = 3   For i = 4 To 30 k = 3 Do k = k + 1 If gcd(k, Y...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#TXR
TXR
#!/usr/bin/txr -f @(next :args) @(cases) @ QUERY @ PAGE @(or) @ (throw error "specify query and page# (from zero)") @(end) @(next (open-command "!wget -O - http://search.yahoo.com/search?p=@QUERY\&b=@{PAGE}1 2> /dev/null")) @(all) @ (coll)<a class="yschttl spt" href="@URL" @/[^>]+/>@TITLE</a>@(end) @(and) @ (coll)...
http://rosettacode.org/wiki/Yahoo!_search_interface
Yahoo! search interface
Create a class for searching Yahoo! results. It must implement a Next Page method, and read URL, Title and Content from results.
#Wren
Wren
/* yahoo_search_interface.wren */   import "./pattern" for Pattern   class YahooSearch { construct new(url, title, desc) { _url = url _title = title _desc = desc }   toString { "URL: %(_url)\nTitle: %(_title)\nDescription: %(_desc)\n" } }   var CURLOPT_URL = 10002 var CURLOPT_FOLLOWL...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#NetRexx
NetRexx
/* NetRexx */   options replace format comments java crossref savelog symbols   import java.math.BigInteger   numeric digits 30 -- needed to report the run-time   nanoFactor = 10 ** 9   t1 = System.nanoTime x = BigInteger.valueOf(5) x = x.pow(BigInteger.valueOf(4).pow(BigInteger.valueOf(3).pow(2).intValue()).intValue()...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Nim
Nim
import bigints   var x = 5.pow 4.pow 3.pow 2 var s = $x   echo s[0..19] echo s[s.high - 19 .. s.high] echo s.len
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#Phixmonti
Phixmonti
def Zeckendorf /# n -- #/ 0 var i 0 var c 1 1 2 tolist var pattern true while i 8 int>bit reverse pattern find not if c print ":\t" print print nl dup c == if false else c 1 + var c true ...
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#PHP
PHP
  <?php $m = 20;   $F = array(1,1); while ($F[count($F)-1] <= $m) $F[] = $F[count($F)-1] + $F[count($F)-2];   while ($n = $m--) { while ($F[count($F)-1] > $n) array_pop($F); $l = count($F)-1; print "$n: "; while ($n) { if ($n >= $F[$l]) { $n = $n - $F[$l]; print '1'; } else ...
http://rosettacode.org/wiki/100_doors
100 doors
There are 100 doors in a row that are all initially closed. You make 100 passes by the doors. The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it). The second time, only visit every 2nd door   (door #2, #4, #6, ...),   and toggle it. The third...
#Cowgol
Cowgol
include "cowgol.coh";   var doors: uint8[101]; # one extra so we can start at 1 var pass: @indexof doors; var door: @indexof doors;   MemZero(&doors as [uint8], @bytesof doors);   pass := 1; while pass <= 100 loop door := pass; while door <= 100 loop doors[door] := 1-doors[door]; door := door +...
http://rosettacode.org/wiki/Arrays
Arrays
This task is about arrays. For hashes or associative arrays, please see Creating an Associative Array. For a definition and in-depth discussion of what an array is, see Array. Task Show basic array syntax in your language. Basically, create an array, assign a value to it, and retrieve an element   (if available,...
#GUISS
GUISS
Start,Programs,Lotus 123,Type:Bob[downarrow],Kat[downarrow],Sarah[downarrow]
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#UNIX_Shell
UNIX Shell
typeset -T Complex_t=( float real=0 float imag=0   function to_s { print -- "${_.real} + ${_.imag} i" }   function dup { nameref other=$1 _=( real=${other.real} imag=${other.imag} ) }   function add { typeset varname for varname; do namere...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#PowerShell
PowerShell
Write-Host "0 ^ 0 = " ([math]::pow(0,0))
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#PureBasic
PureBasic
  If OpenConsole() PrintN("Zero to the zero power is " + Pow(0,0)) PrintN("") PrintN("Press any key to close the console") Repeat: Delay(10) : Until Inkey() <> "" CloseConsole() EndIf  
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Pyret
Pyret
num-expt(0, 0)
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#ERRE
ERRE
  PROGRAM ZEBRA_PUZZLE   DIM DRINK$[4],NATION$[4],COLR$[4],SMOKE$[4],ANIMAL$[4] DIM PERM$[120],X$[4]   PROCEDURE PERMUTATION(X$[]->X$[],OK) LOCAL I%,J% FOR I%=UBOUND(X$,1)-1 TO 0 STEP -1 DO EXIT IF X$[I%]<X$[I%+1] END FOR IF I%<0 THEN OK=FALSE EXIT PROCEDURE END IF J%=UBOUND(X$,1) WHILE ...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Go
Go
package main   import ( "encoding/xml" "fmt" "log" "os" )   type Inventory struct { XMLName xml.Name `xml:"inventory"` Title string `xml:"title,attr"` Sections []struct { XMLName xml.Name `xml:"section"` Name string `xml:"name,attr"` Items []struct { XMLName xml.Name `xml:"item"` Nam...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#Haskell
Haskell
{-# LANGUAGE NoMonomorphismRestriction #-}   import Diagrams.Prelude import Diagrams.Backend.Cairo.CmdLine   yinyang = lw 0 $ perim # lw 0.003 <> torus white black # xform id <> torus black white # xform negate <> clipBy perim base where perim = arc 0 (360 :: Deg) # scale ...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#Delphi
Delphi
program Y;   {$APPTYPE CONSOLE}   uses SysUtils;   type YCombinator = class sealed class function Fix<T> (F: TFunc<TFunc<T, T>, TFunc<T, T>>): TFunc<T, T>; static; end;   TRecursiveFuncWrapper<T> = record // workaround required because of QC #101272 (http://qc.embarcadero.com/wc/qcmain.aspx?d=101272) ty...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#E
E
/** Missing scalar multiplication, but we don't need it. */ def makeVector2(x, y) { return def vector { to x() { return x } to y() { return y } to add(other) { return makeVector2(x + other.x(), y + other.y()) } to clockwise() { return makeVector2(-y, x) } } }   /** Bugs: (1) The printing is speciali...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Vlang
Vlang
fn gcd(xx int, yy int) int { mut x := xx mut y := yy for y != 0 { x, y = y, x%y } return x }   fn yellowstone(n int) []int { mut m := map[int]bool{} mut a := []int{len: n+1} for i in 1..4 { a[i] = i m[i] = true } mut min := 4 for c := 4; c <= n; c++ { ...
http://rosettacode.org/wiki/Yellowstone_sequence
Yellowstone sequence
The Yellowstone sequence, also called the Yellowstone permutation, is defined as: For n <= 3, a(n) = n For n >= 4, a(n) = the smallest number not already in sequence such that a(n) is relatively prime to a(n-1) and is not relatively prime to a(n-2). The sequence is a permutation of the natural n...
#Wren
Wren
import "/math" for Int   var yellowstone = Fn.new { |n| var m = {} var a = List.filled(n + 1, 0) for (i in 1..3) { a[i] = i m[i] = true } var min = 4 for (c in 4..n) { var i = min while (true) { if (!m[i] && Int.gcd(a[c-1], i) == 1 && Int.gcd(a[c-2], i...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#OCaml
OCaml
open Num open Str open String   let () = let answer = (Int 5) **/ (Int 4) **/ (Int 3) **/ (Int 2) in let answer_string = string_of_num answer in Printf.printf "has %d digits: %s ... %s\n" (length answer_string) (first_chars answer_string 20) (last_chars answer_strin...
http://rosettacode.org/wiki/Arbitrary-precision_integers_(included)
Arbitrary-precision integers (included)
Using the in-built capabilities of your language, calculate the integer value of: 5 4 3 2 ...
#Oforth
Oforth
import: mapping   5 4 3 2 pow pow pow >string dup left( 20 ) . dup right( 20 ) . size .
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#Picat
Picat
go => foreach(Num in 0..20) zeckendorf_cp(Num,X,F), Nums = [F[I] : I in 1..X.length, X[I] = 1], printf("%2d %6s %w\n",Num, rep(X),Nums), end, nl.   zeckendorf_cp(Num, X,F) => F = get_fibs(Num).reverse(), N = F.length, X = new_list(N), X :: 0..1,    % From the task description:  % """  % For...
http://rosettacode.org/wiki/Zeckendorf_number_representation
Zeckendorf number representation
Just as numbers can be represented in a positional notation as sums of multiples of the powers of ten (decimal) or two (binary); all the positive integers can be represented as the sum of one or zero times the distinct members of the Fibonacci series. Recall that the first six distinct Fibonacci numbers are: 1, 2, 3, ...
#PicoLisp
PicoLisp
(de fib (N) (let Fibs (1 1) (while (>= N (+ (car Fibs) (cadr Fibs))) (push 'Fibs (+ (car Fibs) (cadr Fibs))) ) (uniq Fibs) ) )   (de zecken1 (N) (make (for I (fib N) (if (> I N) (link 0) (link 1) (dec 'N I) ) ) ) )   (de zecken2 (N) (make ...
http://rosettacode.org/wiki/100_doors
100 doors
There are 100 doors in a row that are all initially closed. You make 100 passes by the doors. The first time through, visit every door and  toggle  the door  (if the door is closed,  open it;   if it is open,  close it). The second time, only visit every 2nd door   (door #2, #4, #6, ...),   and toggle it. The third...
#Crystal
Crystal
doors = Array.new(100, false)   1.upto(100) do |i| i.step(by: i, to: 100) do |j| doors[j - 1] = !doors[j - 1] end end   doors.each_with_index do |open, i| puts "Door #{i + 1} is #{open ? "open" : "closed"}" end
http://rosettacode.org/wiki/Arrays
Arrays
This task is about arrays. For hashes or associative arrays, please see Creating an Associative Array. For a definition and in-depth discussion of what an array is, see Array. Task Show basic array syntax in your language. Basically, create an array, assign a value to it, and retrieve an element   (if available,...
#GW-BASIC
GW-BASIC
10 DATA 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 20 DIM A(9) ' Array with size 10 (9 is maximum subscript), all elements are set to 0 30 FOR I = 0 TO 9 40 READ A(I) ' Initialize by reading data 50 NEXT I 60 PRINT A(4) ' Get 4th element of array 70 A(4) = 400 ' Set 4th element of array 80 PRINT A(4)  
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#Ursala
Ursala
u = 3.785e+00-1.969e+00i v = 9.545e-01-3.305e+00j   #cast %jL   examples =   < complex..add (u,v), complex..mul (u,v), complex..sub (0.,u), complex..div (1.,v)>
http://rosettacode.org/wiki/Arithmetic/Complex
Arithmetic/Complex
A   complex number   is a number which can be written as: a + b × i {\displaystyle a+b\times i} (sometimes shown as: b + a × i {\displaystyle b+a\times i} where   a {\displaystyle a}   and   b {\displaystyle b}   are real numbers,   and   i {\displaystyle i}   is   √ -1  Typica...
#VBA
VBA
  Public Type Complex re As Double im As Double End Type   Function CAdd(a As Complex, b As Complex) As Complex CAdd.re = a.re + b.re CAdd.im = a.im + b.im End Function   Function CSub(a As Complex, b As Complex) As Complex CSub.re = a.re - b.re CSub.im = a.im - b.im End Function   Function CMul...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#Python
Python
from decimal import Decimal from fractions import Fraction from itertools import product   zeroes = [0, 0.0, 0j, Decimal(0), Fraction(0, 1), -0.0, -0.0j, Decimal(-0.0)] for i, j in product(zeroes, repeat=2): try: ans = i**j except: ans = '<Exception raised>' print(f'{i!r:>15} ** {j!r:<15} = ...
http://rosettacode.org/wiki/Zero_to_the_zero_power
Zero to the zero power
Some computer programming languages are not exactly consistent   (with other computer programming languages)   when   raising zero to the zeroth power:     00 Task Show the results of raising   zero   to the   zeroth   power. If your computer language objects to     0**0     or     0^0     at compile time, ...
#QB64
QB64
Print 0 ^ 0
http://rosettacode.org/wiki/Zebra_puzzle
Zebra puzzle
Zebra puzzle You are encouraged to solve this task according to the task description, using any language you may know. The Zebra puzzle, a.k.a. Einstein's Riddle, is a logic puzzle which is to be solved programmatically. It has several variants, one of them this:   There are five houses.   The English man lives ...
#F.23
F#
  (*Here I solve the Zebra puzzle using Plain Changes, definitely a challenge to some campanoligist to solve it using Grandsire Doubles. Nigel Galloway: January 27th., 2017 *) type N = |English=0 |Swedish=1|Danish=2 |German=3|Norwegian=4 type I = |Tea=0 |Coffee=1 |Milk=2 |Beer=3 |Water=4 type G = |Dog=0 ...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Groovy
Groovy
def inventory = new XmlSlurper().parseText("<inventory...") //optionally parseText(new File("inv.xml").text) def firstItem = inventory.section.item[0] //1. first item inventory.section.item.price.each { println it } //2. print each price def allNamesArray = inventory.section.item.n...
http://rosettacode.org/wiki/XML/XPath
XML/XPath
Perform the following three XPath queries on the XML Document below: //item[1]: Retrieve the first "item" element //price/text(): Perform an action on each "price" element (print it out) //name: Get an array of all the "name" elements XML Document: <inventory title="OmniCorp Store #45x10^3"> <section name="heal...
#Haskell
Haskell
import Data.List import Control.Arrow import Control.Monad   takeWhileIncl :: (a -> Bool) -> [a] -> [a] takeWhileIncl _ [] = [] takeWhileIncl p (x:xs) | p x = x : takeWhileIncl p xs | otherwise = [x]   getmultiLineItem n = takeWhileIncl(not.isInfixOf ("</" ++ n)). dropWh...
http://rosettacode.org/wiki/Yin_and_yang
Yin and yang
One well-known symbol of the philosophy of duality known as yin and yang is the taijitu. Task   Create a function that, given a parameter representing size, generates such a symbol scaled to the requested size.   Generate and display the symbol for two different (small) sizes.
#Icon_and_Unicon
Icon and Unicon
link graphics   procedure main() YinYang(100) YinYang(40,"blue","yellow","white") WDone() # quit on Q/q end   procedure YinYang(R,lhs,rhs,bg) # draw YinYang with radius of R pixels and ... /lhs := "white" # left hand side /rhs := "black" # right hand side /bg := "grey" ...
http://rosettacode.org/wiki/Y_combinator
Y combinator
In strict functional programming and the lambda calculus, functions (lambda expressions) don't have state and are only allowed to refer to arguments of enclosing functions. This rules out the usual definition of a recursive function wherein a function is associated with the state of a variable and this variable's stat...
#Dhall
Dhall
let const  : ∀(b : Type) → ∀(a : Type) → a → b → a = λ(r : Type) → λ(a : Type) → λ(x : a) → λ(y : r) → x   let fac  : ∀(n : Natural) → Natural = λ(n : Natural) → let factorial = λ(f : Natural → Natural → Natural) → λ(n : Natural) → λ(i : Natural) → ...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#Elena
Elena
import extensions;   extension op : IntNumber { zigzagMatrix() { auto result := IntMatrix.allocate(self, self);   int i := 0; int j := 0; int d := -1; int start := 0; int end := self*self - 1;   while (start < end) { result.setAt(i, j, ...
http://rosettacode.org/wiki/Zig-zag_matrix
Zig-zag matrix
Task Produce a zig-zag array. A   zig-zag   array is a square arrangement of the first   N2   natural numbers,   where the numbers increase sequentially as you zig-zag along the array's   anti-diagonals. For a graphical representation, see   JPG zigzag   (JPG uses such arrays to encode images). For example, gi...
#Elixir
Elixir
defmodule RC do require Integer def zigzag(n) do fmt = "~#{to_char_list(n*n-1) |> length}w " (for x <- 1..n, y <- 1..n, do: {x,y}) |> Enum.sort_by(fn{x,y}->{x+y, if(Integer.is_even(x+y), do: y, else: x)} end) |> Enum.with_index |> Enum.sort |> Enum.each(fn {{_x,y},i} ->  :io.form...