christopher/rosetta-code · Datasets at Hugging Face

task_url stringlengths 30 116	task_name stringlengths 2 86	task_description stringlengths 0 14.4k	language_url stringlengths 2 53	language_name stringlengths 1 52	code stringlengths 0 61.9k
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#Chef	Chef	Asterisks Omelette. This recipe prints a triangle of asterisks. Ingredients. 5 eggs 1 onion 1 potato 42 ml water 10 ml olive oil 1 garlic Method. Put eggs into the mixing bowl. Fold onion into the mixing bowl. Put eggs into the mixing bowl. Add garlic into the mixing bowl. Fold eggs into the mixing bowl. Chop onion. Put onion into the mixing bowl. Fold potato into the mixing bowl. Put olive oil into the mixing bowl. Mash potato. Put water into the mixing bowl. Mash potato until mashed. Chop onion until choped. Pour contents of the mixing bowl into the baking dish. Serves 1.
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Elixir	Elixir	defmodule Loops do def for_step(n, step) do IO.inspect Enum.take_every(1..n, step) end end Loops.for_step(20, 3)
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lambdatalk	Lambdatalk	{def loops_N_plus_one_half {lambda {:i :n} {if {> :i :n} then (end of loop with a dot) else {if {= :i 6} then {br}:i else :i}{if {= :i :n} then . else ,} {loops_N_plus_one_half {+ :i 1} :n}}}} -> loops_N_plus_one_half {loops_N_plus_one_half 0 10} -> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. (end of loop with a dot)
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Liberty_BASIC	Liberty BASIC	dim ar(10,10) for i = 1 to 10 for j = 1 to 10 ar(i, j) = int(rnd(1) * 20) + 1 next next flag=0 for x = 1 to 10 for y = 1 to 10 print ar(x,y) if ar(x,y) = 20 then flag=1 exit for end if next if flag then exit for next print "Completed row ";x;" and column ";y
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Maple	Maple	for p in [2, 3, 5, 7] do print(p); end do;
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Mathematica.2FWolfram_Language	Mathematica/Wolfram Language	s = (StringSplit@Import["ExampleData/USConstitution.txt"])[[1;;7]]; Do[ Print@i, {i, s} ]
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#GAP	GAP	IsLuhn := function(n) local c, d, i, j, r; d := "0123456789"; j := 1; r := 0; for c in Reversed(String(n)) do i := Position(d, c); if i = fail then continue; fi; i := j*(i - 1); r := r + QuoInt(i, 10) + RemInt(i, 10); j := 3 - j; od; return RemInt(r, 10) = 0; end; List([49927398716, 49927398717, 1234567812345678, 1234567812345670], IsLuhn); # [ true, false, false, true ] # Will also work on strings, and will skip non-digits IsLuhn("4-992-739-871-6"); # true
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#R	R	# vectorized approach based on scalar code from primeSieve and mersenne in CRAN package `numbers` require(gmp) n <- 4423 # note that the sieve below assumes n > 9 # sieve the set of primes up to n p <- seq(1, n, by = 2) q <- length(p) p[1] <- 2 for (k in seq(3, sqrt(n), by = 2)) if (p[(k + 1)/2] != 0) p[seq((k * k + 1)/2, q, by = k)] <- 0 p <- p[p > 0] cat(p[1]," special case M2 == 3\n") p <- p[-1] z2 <- gmp::as.bigz(2) z4 <- z2 * z2 zp <- gmp::as.bigz(p) zmp <- z2^zp - 1 S <- rep(z4, length(p)) for (i in 1:(p[length(p)] - 2)){ S <- gmp::mod.bigz(S * S - z2, zmp) if( i+2 == p[1] ){ if( S[1] == 0 ){ cat( p[1], "\n") flush.console() } p <- p[-1] zmp <- zmp[-1] S <- S[-1] } }
http://rosettacode.org/wiki/LZW_compression	LZW compression	The Lempel-Ziv-Welch (LZW) algorithm provides loss-less data compression. You can read a complete description of it in the Wikipedia article on the subject. It was patented, but it entered the public domain in 2004.	#zkl	zkl	fcn lzwCompress(uncompressed){ // text-->list of 12 bit ints dictionary:=(256).pump(Dictionary(),fcn(n){ return(n.toChar(),n) }); w,compressed:="",List(); foreach c in (uncompressed){ wc:=w+c; if(dictionary.holds(wc)) w=wc; else{ compressed.append(dictionary[w]); // 12 bits dictionary[wc]=dictionary.len(); w=c; } } if(w) compressed.append(dictionary[w]); compressed } fcn lzwUncompress(compressed){ // compressed data-->text dictionary:=(256).pump(Dictionary(),fcn(n){ return(n,n.toChar()) }); w,decommpressed:=dictionary[compressed[0]],Data(Void,w); foreach k in (compressed[1,*]){ if(dictionary.holds(k)) entry:=dictionary[k]; else if(k==dictionary.len()) entry:=w+w[0]; else throw(Exception.ValueError("Invalid compressed data")); decommpressed.append(entry); dictionary.add(dictionary.len(),w+entry[0]); w=entry; } decommpressed.text }
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#hexiscript	hexiscript	while true; println "SPAM"; endwhile
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#HicEst	HicEst	DO i = 1, 1E20 ! for i with 16 or more digits: i == i + 1 == loop infinite WRITE() "SPAM" ENDDO
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Go	Go	i := 1024 for i > 0 { fmt.Printf("%d\n", i) i /= 2 }
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Fortran	Fortran	DO i = 10, 0, -1 WRITE(, ) i END DO
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#DWScript	DWScript	var i := 0; repeat Inc(i); PrintLn(i); until i mod 6 = 0;
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#Clojure	Clojure	(doseq [i (range 5), j (range (inc i))] (print "*") (if (= i j) (println)))
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Erlang	Erlang	%% Implemented by Arjun Sunel %% for_loop/4 by Bengt Kleberg. -module(loop_step). -export([main/0, for_loop/1, for_loop/4]). % This Erlang code for "For Loop" is equivalent to: " for (i=start; i<end ; i=i+2){ printf("* ");} " in C language. main() -> for_loop(1). for_loop( N ) -> for_loop( N, 4, 2, fun() -> io:fwrite("* ") end ). for_loop( I, End, Step, Do ) when N < End -> Do(), for_loop( I+Step, End, Step, Do ); for_loop( _I, _End, _Step, _Do ) -> ok.
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lang5	Lang5	: , dup ", " 2 compress "" join ; 1 do dup 10 != if dup , . 1 + else . break then loop
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lasso	Lasso	local(out) = '' loop(10) => { #out->append(loop_count) loop_count == 10 ? loop_abort #out->append(', ') } #out
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lingo	Lingo	-- create two-dimensional array with random numbers a = [] repeat with i = 1 to 20 a[i] = [] repeat with j = 1 to 20 a[i][j] = random(20) end repeat end repeat -- iterate over rows and columns, print value, exit both loops if it's 20 repeat with i = 1 to 20 repeat with j = 1 to 20 v = a[i][j] put v if v=20 then exit repeat end repeat if v=20 then exit repeat end repeat
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#MATLAB_.2F_Octave	MATLAB / Octave	list1 = [1,5,6,7,-7,-9]; for k = list1, % list1 must be a row vector (i.e. array of size 1xn) printf('%i\n',k) end;
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Maxima	Maxima	for n in [2, 3, 5, 7] do print(n);
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#Go	Go	package main import ( "fmt" "strings" ) const input = `49927398716 49927398717 1234567812345678 1234567812345670` var t = [...]int{0, 2, 4, 6, 8, 1, 3, 5, 7, 9} func luhn(s string) bool { odd := len(s) & 1 var sum int for i, c := range s { if c < '0' \|\| c > '9' { return false } if i&1 == odd { sum += t[c-'0'] } else { sum += int(c - '0') } } return sum%10 == 0 } func main() { for _, s := range strings.Split(input, "\n") { fmt.Println(s, luhn(s)) } }
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#Racket	Racket	#lang racket (require math) (define (mersenne-prime? p) (divides? (- (expt 2 p) 1) (S (- p 1)))) (define (S n) (if (= n 1) 4 (- (sqr (S (- n 1))) 2))) (define (loop p) (when (mersenne-prime? p) (displayln p)) (loop (next-prime p))) (loop 3)
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#HolyC	HolyC	while(1) Print("SPAM\n");
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Icon_and_Unicon	Icon and Unicon	procedure main() repeat write("SPAM") end
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Groovy	Groovy	int i = 1024 while (i > 0) { println i i /= 2 }
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Haskell	Haskell	import Control.Monad (when) main = loop 1024 where loop n = when (n > 0) (do print n loop (n `div` 2))
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Frink	Frink	for i = 10 to 0 step -1 println[i]
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#GAP	GAP	for i in [10, 9 .. 0] do Print(i, "\n"); od;
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#Dyalect	Dyalect	var x = 0 do { x += 1 print(x) } while x % 6 != 0
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#E	E	var x := 0 __loop(fn { x += 1 println(x) x % 6 != 0 # this is the return value of the function })
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#CLU	CLU	start_up = proc () po: stream := stream$primary_output() for i: int in int$from_to(1, 5) do for j: int in int$from_to(1, i) do stream$putc(po, '*') end stream$putl(po, "") end end start_up
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#ERRE	ERRE	FOR N=2 TO 8 STEP 1.5 DO PRINT(N) END FOR
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lhogho	Lhogho	for "i [1 10] [ type :i if :i < 10 [ type "\|, \| ] ] print
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Liberty_BASIC	Liberty BASIC	for i =1 to 10 print i; if i =10 then exit for print ", "; next i end
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lisaac	Lisaac	Section Header + name := TEST_LOOP_NESTED; - external := `#include <time.h>`; Section Public - main <- ( + a : ARRAY2[INTEGER]; + i, j: INTEGER; `srand(time(NULL))`; a := ARRAY2[INTEGER].create(0, 0) to (9, 9); 0.to 9 do { ii : INTEGER; 0.to 9 do { jj : INTEGER; a.put (`rand()`:INTEGER % 20 + 1) to (ii, jj); }; }; { i < 10 }.while_do { j := 0; { j < 10 }.while_do { ' '.print; a.item(i, j).print; (a.item(i, j) = 20).if { i := 999; j := 999; }; j := j + 1; }; i := i + 1; '\n'.print; }; '\n'.print; );
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#LiveCode	LiveCode	repeat with i = 1 to 10 repeat with j = 1 to 10 put random(20) into aNums[i,j] end repeat end repeat repeat with i = 1 to 10 repeat with j = 1 to 10 if aNums[i,j] = 20 then put true into exitLoop exit repeat end if end repeat if exitLoop then exit repeat end repeat if exitLoop then put "20 found in" && i & comma & j else put "20 not found" end if
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#MAXScript	MAXScript	arr = for i in 1 to 50 collect ("Number: " + (random 10 99) as string) makeuniquearray arr sort arr for i in arr do print i as string
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Metafont	Metafont	for x = "mary", "had", "a", "little", "lamb": message x; endfor end
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#Groovy	Groovy	def checkLuhn(number) { int total (number as String).reverse().eachWithIndex { ch, index -> def digit = Integer.parseInt(ch) total += (index % 2 ==0) ? digit : [0, 2, 4, 6, 8, 1, 3, 5, 7, 9][digit] } total % 10 == 0 }
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#Raku	Raku	multi is_mersenne_prime(2) { True } multi is_mersenne_prime(Int $p) { my $m_p = 2 ** $p - 1; my $s = 4; $s = $s.expmod(2, $m_p) - 2 for 3 .. $p; !$s } .say for (2,3,5,7 … ).hyper(:8degree).grep( .is-prime ).map: { next unless .&is_mersenne_prime; "M$_" };
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#IDL	IDL	while 1 do print,'SPAM'
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Intercal	Intercal	NOTE THIS IS INTERCAL PLEASE ,1 <- #5 DO ,1 SUB #1 <- #54 DO ,1 SUB #2 <- #192 DO ,1 SUB #3 <- #136 PLEASE ,1 SUB #4 <- #208 DO ,1 SUB #5 <- #98 DO COME FROM (1) DO READ OUT ,1 (2) DO ,1 SUB #1 <- #134 (1) PLEASE ABSTAIN FROM (2)
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Haxe	Haxe	var i = 1024; while (i > 0) { Sys.println(i); i >>= 1; }
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#hexiscript	hexiscript	let i 1024 while i > 0 println i let i (i / 2) endwhile
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#GML	GML	for(i = 10; i >= 0; i -= 1) show_message(string(i))
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Go	Go	for i := 10; i >= 0; i-- { fmt.Println(i) }
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#Ela	Ela	open monad io loop n \| n % 6 == 0 = do return () \| else = do putStrLn (show n) loop (n+1) _ = loop 10 ::: IO
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#COBOL	COBOL	IDENTIFICATION DIVISION. PROGRAM-ID. Display-Triangle. DATA DIVISION. WORKING-STORAGE SECTION. 01 Outer-Counter PIC 9. 01 Inner-Counter PIC 9. PROCEDURE DIVISION. PERFORM VARYING Outer-Counter FROM 1 BY 1 UNTIL 5 < Outer-Counter PERFORM VARYING Inner-Counter FROM 1 BY 1 UNTIL Outer-Counter < Inner-Counter DISPLAY "" NO ADVANCING END-PERFORM DISPLAY "" > Output a newline END-PERFORM GOBACK .
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Euphoria	Euphoria	for i = 1 to 10 by 2 do ? i end for
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lisaac	Lisaac	Section Header + name := LOOP_AND_HALF; Section Public - main <- ( + i : INTEGER; i := 1; { i.print; i = 10 }.until_do { ", ".print; i := i + 1; }; '\n'.print; );
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#LiveCode	LiveCode	repeat with n = 1 to 10 put n after loopn if n is not 10 then put comma after loopn end repeat put loopn
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Logo	Logo	make "a mdarray [10 10] for [j 1 10] [for [i 1 10] [mdsetitem list :i :j :a (1 + random 20)]] to until.20 for [j 1 10] [ for [i 1 10] [ type mditem list :i :j :a type "\| \| if equal? 20 mditem list :i :j :a [stop] ] print "\|\| ] end until.20
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lua	Lua	t = {} for i = 1, 20 do t[i] = {} for j = 1, 20 do t[i][j] = math.random(20) end end function exitable() for i = 1, 20 do for j = 1, 20 do if t[i][j] == 20 then return i, j end end end end print(exitable())
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#min	min	(1 2 3) 'puts foreach
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#MiniScript	MiniScript	for i in collection print i end
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#Haskell	Haskell	import Data.Char (digitToInt) luhn = (0 ==) . (`mod` 10) . sum . map (uncurry (+) . (`divMod` 10)) . zipWith (*) (cycle [1,2]) . map digitToInt . reverse
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#REXX	REXX	/REXX pgm uses the Lucas─Lehmer primality test for prime powers of 2 (Mersenne primes)/ @.=0; @.2=1; @.3=1; @.5=1; @.7=1; @.11=1; @.13=1 /a partial list of some low primes. / !.=@.; !.0=1; !.2=1; !.4=1; !.5=1; !.6=1; !.8=1 /#'s with these last digs aren't prime/ parse arg limit . /obtain optional arguments from the CL/ if limit=='' then limit= 200 /Not specified? Then use the default./ say center('Mersenne prime index list',70-3,"═") /show a fancy─dancy header (or title)./ say right('M'2, 25) " [1 decimal digit]" /left─justify them to align&look nice./ /* [►] note that J==1 is a special case/ do j=1 by 2 to limit /there're only so many hours in a day./ power= j + (j==1) /POWER ≡ J except for when J=1. / if \isPrime(power) then iterate /if POWER isn't prime, then ignore it./ $= LL2(power) /perform the Lucas─Lehmer 2 (LL2) test/ if $=='' then iterate /Did it flunk LL2? Then skip this #./ say right($, 25) MPsize /left─justify them to align&look nice./ end /j/ exit /stick a fork in it, we're all done. / /──────────────────────────────────────────────────────────────────────────────────────/ isPrime: procedure expose !. @. /allow 2 stemmed arrays to be accessed/ parse arg x '' -1 z /obtain variable X and last digit./ if @.x then return 1 /is X already found to be a prime? / if !.z then return 0 /is last decimal digit even or a five?/ if x//3==0 then return 0 /divisible by three? Then not a prime/ if x//7==0 then return 0 /divisible by seven? " " " " / do j=11 by 6 until jj > x /ensures that J isn't divisible by 3. / if x // j ==0 then return 0 /Is X divisible by J ? / if x // (j+2)==0 then return 0 /* " " " " J+2 ? ___ / end /j/ / [↑] perform DO loop through √ x / @.x=1; return 1 /indicate number X is a prime. / /──────────────────────────────────────────────────────────────────────────────────────/ LL2: procedure expose MPsize; parse arg ? /Lucas─Lehmer test on 2*? - 1 / if ?==2 then s=0 /handle special case for an even prime/ else s=4 /* [↓] same as NUMERIC FORM SCIENTIFIC/ numeric form; q= 2? /ensure correct form for REXX numbers./ /╔═══════════════════════════════════════════════════════════════════════════╗ ╔═╝ Compute a power of 2 using only 9 decimal digits. One million digits ║ ║ could be used, but that really slows up computations. So, we start with the║ ║ default of 9 digits, and then find the ten's exponent in the product (2*?),║ ║ double it, and then add 6. {2 is all that's needed, but 6 is a lot ║ ║ safer.} The doubling is for the squaring of S (below, for ss). ╔═╝ ╚═══════════════════════════════════════════════════════════════════════════╝/ if pos('E', q)\==0 then do /is number in exponential notation ? / parse var q 'E' tenPow /get the exponent. / numeric digits tenPow 2 + 6 /expand precision. / end /REXX used dec FP. / else numeric digits digits() * 2 + 6 /use 92 + 6 digits/ q=2? - 1 /compute a power of two, minus one. / r= q // 8 /obtain Q modulus eight. / if r==1 \| r==7 then nop /before crunching, do a simple test. / else return '' /modulus Q isn't one or seven. / do ?-2; s= (ss -2) // q /lather, rinse, repeat ··· / end /* [↑] compute and test for a MP. / if s\==0 then return '' /Not a Mersenne prime? Return a null./ sz= length(q) /obtain number of decimal digs in MP. / MPsize=' ['sz "decimal digit"s(sz)']' /define a literal to display after MP./ return 'M'? /return "modified" # (Mersenne index)./ /──────────────────────────────────────────────────────────────────────────────────────/ s: if arg(1)==1 then return arg(3); return word(arg(2) 's', 1) /simple pluralizer*/
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Io	Io	loop("SPAM" println)
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#J	J	(-[smoutput bind 'SPAM')^:_(1)
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#HolyC	HolyC	U16 i = 1024; while (i > 0) { Print("%d\n", i); i /= 2; }
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Icon_and_Unicon	Icon and Unicon	procedure main() local i i := 1024 while write(0 < (i := i / 2)) end
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Groovy	Groovy	for (i in (10..0)) { println i }
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#Elixir	Elixir	defmodule Loops do def do_while(n) do n1 = n + 1 IO.puts n1 if rem(n1, 6) == 0, do: :ok, else: do_while(n1) end end Loops.do_while(0)
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#ColdFusion	ColdFusion	<cfloop index = "i" from = "1" to = "5"> <cfloop index = "j" from = "1" to = "#i#"> * </cfloop> < br /> </cfloop>
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#F.23	F#	for i in 2..2..8 do printf "%d, " i printfn "done"
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Logo	Logo	to comma.list :n repeat :n-1 [type repcount type "\|, \|] print :n end comma.list 10
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Lua	Lua	for i = 1, 10 do io.write(i) if i == 10 then break end io.write", " end
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#M2000_Interpreter	M2000 Interpreter	Module Checkit { Dim A(10,10)<<Random(1, 20) For k=1 to 2 { For i=0 to 9 { For j=0 to 9 { Print A(i,j) if A(i,j)=20 then goto there } } there: Print "...ok", k } } Checkit
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Maple	Maple	(m,n) := LinearAlgebra:-Dimensions(M): for i from 1 to m do for j from 1 to n do print(M[i,j]); if M[i,j] = 20 then (i,j):=m,n; next; end if; end do; end do:
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#MOO	MOO	things = {"Apple", "Banana", "Coconut"}; for thing in (things) player:tell(thing); endfor
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Nanoquery	Nanoquery	for item in collection println item end
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#HicEst	HicEst	CHARACTER numbers="49927398716 49927398717 1234567812345678 1234567812345670 " DO nr = 1, 4 EDIT(Text=numbers, ITeM=nr, Parse=number) sum_odds = 0 sum_even = 0 DO i = LEN(number), 1, -2 sum_odds = sum_odds + ICHAR(number(i)) - 48 IF(i > 1) THEN even2 = 2 * (ICHAR(number(i-1)) - 48) sum_even = sum_even + MOD(even2, 10) + INT(even2/10) ENDIF ENDDO valid = (0 == MOD(sum_odds + sum_even, 10)) WRITE() number, " is ", "invalid"(1 + 2*valid:) ENDDO
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#Ring	Ring	see "Mersenne Primes :" + nl for p = 2 to 18 if lucasLehmer(p) see "M" + p + nl ok next func lucasLehmer p i = 0 mp = 0 sn = 0 if p = 2 return true ok if (p and 1) = 0 return false ok mp = pow(2,p) - 1 sn = 4 for i = 3 to p sn = pow(sn,2) - 2 sn -= (mp * floor(sn / mp)) next return (sn=0)
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Java	Java	while (true) { System.out.println("SPAM"); }
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#JavaScript	JavaScript	for (;;) console.log("SPAM");
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Inform_7	Inform 7	let N be 1024; while N > 0: say "[N][line break]"; let N be N / 2;
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#IWBASIC	IWBASIC	DEF X:INT X=1024 OPENCONSOLE WHILE X>0 PRINT X X=X/2 ENDWHILE 'Output starts with 1024 and ends with 1. 'Putting the following in the loop will produce output starting with 512 and ending with 0: 'X=X/2 'PRINT X 'When compiled as a console only program, a press any key to continue message is automatic. 'I presume code is added by the compiler. CLOSECONSOLE 'Since this is, in fact, an IWBASIC console program, which compiles and runs. END
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Harbour	Harbour	FOR i := 10 TO 0 STEP -1 ? i NEXT
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Haskell	Haskell	import Control.Monad main :: IO () main = forM_ [10,9 .. 0] print
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#Emacs_Lisp	Emacs Lisp	(let ((val 0)) (while (progn (setq val (1+ val)) (message "%d" val) (/= 0 (mod val 6)))))
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#Common_Lisp	Common Lisp	(loop for i from 1 upto 5 do (loop for j from 1 upto i do (write-char #\*)) (terpri))
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Factor	Factor	1 10 2 <range> [ . ] each
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#M2000_Interpreter	M2000 Interpreter	Module Checkit { \\ old type loop For i=1 to 10 Print i; If i=10 Then Exit For Print ", "; Next i Print \\ fast type loop. Continue exit block, without breaking loop. For i=1 to 10 { Print i; If i=10 Then Continue Print ", "; } Print Print i=0 { loop \\ this mark block for loop, each time need to mark i++ Print i; If i=10 Then Exit ' so now we use exit to break loop Print ", "; } Print } Checkit
http://rosettacode.org/wiki/Loops/N_plus_one_half	Loops/N plus one half	Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#M4	M4	define(`break', `define(`ulim',llim)') define(`for', `ifelse($#,0,``$0'', `define(`ulim',$3)`'define(`llim',$2)`'ifelse(ifelse($3,`',1, `eval($2<=$3)'),1, `pushdef(`$1',$2)$4`'popdef(`$1')$0(`$1',incr($2),ulim,`$4')')')') for(`x',`1',`', `x`'ifelse(x,10,`break',`, ')')
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Mathematica.2FWolfram_Language	Mathematica/Wolfram Language	Do[ Print[m[[i, j]]]; If[m[[i, j]] === 20, Return[]], {i, 1, Dimensions[m][[1]]}, {j, 1, Dimensions[m][[2]]}]
http://rosettacode.org/wiki/Loops/Nested	Loops/Nested	Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#MATLAB_.2F_Octave	MATLAB / Octave	a = ceil(rand(100,100)*20); [ix,iy]=find(a==20,1)
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Nemerle	Nemerle	def things = ["Apple", "Banana", "Coconut"]; foreach (thing in things) WriteLine(thing.ToLower()); foreach (i in [5, 10 .. 100]) Write($"$i\t");
http://rosettacode.org/wiki/Loops/Foreach	Loops/Foreach	Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#NetRexx	NetRexx	/* NetRexx */ options replace format comments java crossref savelog symbols nobinary say say 'Loops/Foreach' days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'] daysl = Arrays.asList(days) daysi = daysl.iterator loop while daysi.hasNext say daysi.next end
http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers	Luhn test of credit card numbers	The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN	#Icon_and_Unicon	Icon and Unicon	procedure main(aL) every write(i := !aL ," - ", ((\isluhn10(i),"valid")\|"invalid") \ 1) end procedure isluhn10(i) #: isluhn10(i) returns i (if i passes luhn10) or fails local sum sum :=0 reverse(integer(i)) ? while not pos(0) do { sum +:= move(1) sum +:= map(move(1),"0123456789","0246813579") } return (sum % 10 = 0,i) end
http://rosettacode.org/wiki/Lucas-Lehmer_test	Lucas-Lehmer test	Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).	#RPL	RPL	%%HP: T(3)A(R)F(.); ; ASCII transfer header \<< DUP LN DUP \pi * 4 SWAP / 1 + UNROT / * IP 2 { 2 } ROT 2 SWAP ; input n; n := Int(n/ln(n)(1 + 4/(piln(n)))), p:=2; (n ~ number of primes less then n, pi used here only as a convenience), 2 is assumed to be the 1st elemente in the list START SWAP NEXTPRIME DUP UNROT DUP 2 SWAP ^ 1 - 4 PICK3 2 - 1 SWAP ; for i := 2 to n, p := nextprime; s := 4; m := 2^p - 1; START SQ 2 - OVER MOD ; for j := 1 to p - 2; s := s^2 mod m; NEXT NIP NOT { + } { DROP } IFTE ; next j; if s = 0 then add p to the list else discard p; NEXT NIP ; next i; \>>
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Joy	Joy	DEFINE loop == [true []] dip while. ["SPAM\n" putchars] loop.
http://rosettacode.org/wiki/Loops/Infinite	Loops/Infinite	Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#jq	jq	recurse("SPAM")
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#J	J	,. <.@-:^:*^:a: 1024
http://rosettacode.org/wiki/Loops/While	Loops/While	Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Java	Java	int i = 1024; while(i > 0){ System.out.println(i); i >>= 1; //also acceptable: i /= 2; }
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#Haxe	Haxe	class Step { var end:Int; var step:Int; var index:Int; public inline function new(start:Int, end:Int, step:Int) { this.index = start; this.end = end; this.step = step; } public inline function hasNext() return step > 0 ? end >= index : index >= end; public inline function next() return (index += step) - step; } class Main { static function main() { for (i in new Step(10, 0, -1)) { Sys.print('$i '); } } }
http://rosettacode.org/wiki/Loops/Downward_for	Loops/Downward for	Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#hexiscript	hexiscript	for let i 10; i >= 0; i-- println i endfor
http://rosettacode.org/wiki/Loops/Do-while	Loops/Do-while	Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.	#Erlang	Erlang	do() -> do(0). do(0) -> io:fwrite( "0 " ), do( 1 ); do(N) when N rem 6 =:= 0 -> io:format("~w~n", [N]); do(N) -> io:fwrite( "~p ", [N] ), do(N+1).
http://rosettacode.org/wiki/Loops/For	Loops/For	“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * * ** *** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.	#Coq	Coq	Section FOR. Variable T : Type. Variable body : nat -> T -> T. Variable start : nat. Fixpoint for_loop n : T -> T := match n with \| O => fun s => s \| S n' => fun s => for_loop n' (body (start + n') s) end. End FOR. Eval vm_compute in for_loop _ (fun i => cons (for_loop _ (fun j => cons tt) 0 (S i) nil ) ) 0 5 nil.
http://rosettacode.org/wiki/Loops/For_with_a_specified_step	Loops/For with a specified step	Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges	#FALSE	FALSE	2[$9\>][$.", "2+]#"who do we appreciate!"

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#Chef

Chef

Asterisks Omelette. This recipe prints a triangle of asterisks. Ingredients. 5 eggs 1 onion 1 potato 42 ml water 10 ml olive oil 1 garlic Method. Put eggs into the mixing bowl. Fold onion into the mixing bowl. Put eggs into the mixing bowl. Add garlic into the mixing bowl. Fold eggs into the mixing bowl. Chop onion. Put onion into the mixing bowl. Fold potato into the mixing bowl. Put olive oil into the mixing bowl. Mash potato. Put water into the mixing bowl. Mash potato until mashed. Chop onion until choped. Pour contents of the mixing bowl into the baking dish. Serves 1.

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Elixir

Elixir

defmodule Loops do def for_step(n, step) do IO.inspect Enum.take_every(1..n, step) end end Loops.for_step(20, 3)

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lambdatalk

Lambdatalk

{def loops_N_plus_one_half {lambda {:i :n} {if {> :i :n} then (end of loop with a dot) else {if {= :i 6} then {br}:i else :i}{if {= :i :n} then . else ,} {loops_N_plus_one_half {+ :i 1} :n}}}} -> loops_N_plus_one_half {loops_N_plus_one_half 0 10} -> 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. (end of loop with a dot)

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Liberty_BASIC

Liberty BASIC

dim ar(10,10) for i = 1 to 10 for j = 1 to 10 ar(i, j) = int(rnd(1) * 20) + 1 next next flag=0 for x = 1 to 10 for y = 1 to 10 print ar(x,y) if ar(x,y) = 20 then flag=1 exit for end if next if flag then exit for next print "Completed row ";x;" and column ";y

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Maple

Maple

for p in [2, 3, 5, 7] do print(p); end do;

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Mathematica.2FWolfram_Language

Mathematica/Wolfram Language

s = (StringSplit@Import["ExampleData/USConstitution.txt"])[[1;;7]]; Do[ Print@i, {i, s} ]

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#GAP

GAP

IsLuhn := function(n) local c, d, i, j, r; d := "0123456789"; j := 1; r := 0; for c in Reversed(String(n)) do i := Position(d, c); if i = fail then continue; fi; i := j*(i - 1); r := r + QuoInt(i, 10) + RemInt(i, 10); j := 3 - j; od; return RemInt(r, 10) = 0; end; List([49927398716, 49927398717, 1234567812345678, 1234567812345670], IsLuhn); # [ true, false, false, true ] # Will also work on strings, and will skip non-digits IsLuhn("4-992-739-871-6"); # true

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#R

R

# vectorized approach based on scalar code from primeSieve and mersenne in CRAN package `numbers` require(gmp) n <- 4423 # note that the sieve below assumes n > 9 # sieve the set of primes up to n p <- seq(1, n, by = 2) q <- length(p) p[1] <- 2 for (k in seq(3, sqrt(n), by = 2)) if (p[(k + 1)/2] != 0) p[seq((k * k + 1)/2, q, by = k)] <- 0 p <- p[p > 0] cat(p[1]," special case M2 == 3\n") p <- p[-1] z2 <- gmp::as.bigz(2) z4 <- z2 * z2 zp <- gmp::as.bigz(p) zmp <- z2^zp - 1 S <- rep(z4, length(p)) for (i in 1:(p[length(p)] - 2)){ S <- gmp::mod.bigz(S * S - z2, zmp) if( i+2 == p[1] ){ if( S[1] == 0 ){ cat( p[1], "\n") flush.console() } p <- p[-1] zmp <- zmp[-1] S <- S[-1] } }

http://rosettacode.org/wiki/LZW_compression

LZW compression

The Lempel-Ziv-Welch (LZW) algorithm provides loss-less data compression. You can read a complete description of it in the Wikipedia article on the subject. It was patented, but it entered the public domain in 2004.

#zkl

zkl

fcn lzwCompress(uncompressed){ // text-->list of 12 bit ints dictionary:=(256).pump(Dictionary(),fcn(n){ return(n.toChar(),n) }); w,compressed:="",List(); foreach c in (uncompressed){ wc:=w+c; if(dictionary.holds(wc)) w=wc; else{ compressed.append(dictionary[w]); // 12 bits dictionary[wc]=dictionary.len(); w=c; } } if(w) compressed.append(dictionary[w]); compressed } fcn lzwUncompress(compressed){ // compressed data-->text dictionary:=(256).pump(Dictionary(),fcn(n){ return(n,n.toChar()) }); w,decommpressed:=dictionary[compressed[0]],Data(Void,w); foreach k in (compressed[1,*]){ if(dictionary.holds(k)) entry:=dictionary[k]; else if(k==dictionary.len()) entry:=w+w[0]; else throw(Exception.ValueError("Invalid compressed data")); decommpressed.append(entry); dictionary.add(dictionary.len(),w+entry[0]); w=entry; } decommpressed.text }

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#hexiscript

hexiscript

while true; println "SPAM"; endwhile

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#HicEst

HicEst

DO i = 1, 1E20 ! for i with 16 or more digits: i == i + 1 == loop infinite WRITE() "SPAM" ENDDO

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Go

Go

i := 1024 for i > 0 { fmt.Printf("%d\n", i) i /= 2 }

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Fortran

Fortran

DO i = 10, 0, -1 WRITE(*, *) i END DO

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#DWScript

DWScript

var i := 0; repeat Inc(i); PrintLn(i); until i mod 6 = 0;

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#Clojure

Clojure

(doseq [i (range 5), j (range (inc i))] (print "*") (if (= i j) (println)))

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Erlang

Erlang

%% Implemented by Arjun Sunel %% for_loop/4 by Bengt Kleberg. -module(loop_step). -export([main/0, for_loop/1, for_loop/4]). % This Erlang code for "For Loop" is equivalent to: " for (i=start; i<end ; i=i+2){ printf("* ");} " in C language. main() -> for_loop(1). for_loop( N ) -> for_loop( N, 4, 2, fun() -> io:fwrite("* ") end ). for_loop( I, End, Step, Do ) when N < End -> Do(), for_loop( I+Step, End, Step, Do ); for_loop( _I, _End, _Step, _Do ) -> ok.

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lang5

Lang5

: , dup ", " 2 compress "" join ; 1 do dup 10 != if dup , . 1 + else . break then loop

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lasso

Lasso

local(out) = '' loop(10) => { #out->append(loop_count) loop_count == 10 ? loop_abort #out->append(', ') } #out

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lingo

Lingo

-- create two-dimensional array with random numbers a = [] repeat with i = 1 to 20 a[i] = [] repeat with j = 1 to 20 a[i][j] = random(20) end repeat end repeat -- iterate over rows and columns, print value, exit both loops if it's 20 repeat with i = 1 to 20 repeat with j = 1 to 20 v = a[i][j] put v if v=20 then exit repeat end repeat if v=20 then exit repeat end repeat

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#MATLAB_.2F_Octave

MATLAB / Octave

list1 = [1,5,6,7,-7,-9]; for k = list1, % list1 must be a row vector (i.e. array of size 1xn) printf('%i\n',k) end;

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Maxima

Maxima

for n in [2, 3, 5, 7] do print(n);

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#Go

Go

package main import ( "fmt" "strings" ) const input = `49927398716 49927398717 1234567812345678 1234567812345670` var t = [...]int{0, 2, 4, 6, 8, 1, 3, 5, 7, 9} func luhn(s string) bool { odd := len(s) & 1 var sum int for i, c := range s { if c < '0' || c > '9' { return false } if i&1 == odd { sum += t[c-'0'] } else { sum += int(c - '0') } } return sum%10 == 0 } func main() { for _, s := range strings.Split(input, "\n") { fmt.Println(s, luhn(s)) } }

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#Racket

Racket

#lang racket (require math) (define (mersenne-prime? p) (divides? (- (expt 2 p) 1) (S (- p 1)))) (define (S n) (if (= n 1) 4 (- (sqr (S (- n 1))) 2))) (define (loop p) (when (mersenne-prime? p) (displayln p)) (loop (next-prime p))) (loop 3)

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#HolyC

HolyC

while(1) Print("SPAM\n");

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Icon_and_Unicon

Icon and Unicon

procedure main() repeat write("SPAM") end

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Groovy

Groovy

int i = 1024 while (i > 0) { println i i /= 2 }

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Haskell

Haskell

import Control.Monad (when) main = loop 1024 where loop n = when (n > 0) (do print n loop (n `div` 2))

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Frink

Frink

for i = 10 to 0 step -1 println[i]

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#GAP

GAP

for i in [10, 9 .. 0] do Print(i, "\n"); od;

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#Dyalect

Dyalect

var x = 0 do { x += 1 print(x) } while x % 6 != 0

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#E

E

var x := 0 __loop(fn { x += 1 println(x) x % 6 != 0 # this is the return value of the function })

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#CLU

CLU

start_up = proc () po: stream := stream$primary_output() for i: int in int$from_to(1, 5) do for j: int in int$from_to(1, i) do stream$putc(po, '*') end stream$putl(po, "") end end start_up

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#ERRE

ERRE

FOR N=2 TO 8 STEP 1.5 DO PRINT(N) END FOR

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lhogho

Lhogho

for "i [1 10] [ type :i if :i < 10 [ type "|, | ] ] print

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Liberty_BASIC

Liberty BASIC

for i =1 to 10 print i; if i =10 then exit for print ", "; next i end

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lisaac

Lisaac

Section Header + name := TEST_LOOP_NESTED; - external := `#include <time.h>`; Section Public - main <- ( + a : ARRAY2[INTEGER]; + i, j: INTEGER; `srand(time(NULL))`; a := ARRAY2[INTEGER].create(0, 0) to (9, 9); 0.to 9 do { ii : INTEGER; 0.to 9 do { jj : INTEGER; a.put (`rand()`:INTEGER % 20 + 1) to (ii, jj); }; }; { i < 10 }.while_do { j := 0; { j < 10 }.while_do { ' '.print; a.item(i, j).print; (a.item(i, j) = 20).if { i := 999; j := 999; }; j := j + 1; }; i := i + 1; '\n'.print; }; '\n'.print; );

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#LiveCode

LiveCode

repeat with i = 1 to 10 repeat with j = 1 to 10 put random(20) into aNums[i,j] end repeat end repeat repeat with i = 1 to 10 repeat with j = 1 to 10 if aNums[i,j] = 20 then put true into exitLoop exit repeat end if end repeat if exitLoop then exit repeat end repeat if exitLoop then put "20 found in" && i & comma & j else put "20 not found" end if

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#MAXScript

MAXScript

arr = for i in 1 to 50 collect ("Number: " + (random 10 99) as string) makeuniquearray arr sort arr for i in arr do print i as string

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Metafont

Metafont

for x = "mary", "had", "a", "little", "lamb": message x; endfor end

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#Groovy

Groovy

def checkLuhn(number) { int total (number as String).reverse().eachWithIndex { ch, index -> def digit = Integer.parseInt(ch) total += (index % 2 ==0) ? digit : [0, 2, 4, 6, 8, 1, 3, 5, 7, 9][digit] } total % 10 == 0 }

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#Raku

Raku

multi is_mersenne_prime(2) { True } multi is_mersenne_prime(Int $p) { my $m_p = 2 ** $p - 1; my $s = 4; $s = $s.expmod(2, $m_p) - 2 for 3 .. $p; !$s } .say for (2,3,5,7 … *).hyper(:8degree).grep( *.is-prime ).map: { next unless .&is_mersenne_prime; "M$_" };

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#IDL

IDL

while 1 do print,'SPAM'

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Intercal

Intercal

NOTE THIS IS INTERCAL PLEASE ,1 <- #5 DO ,1 SUB #1 <- #54 DO ,1 SUB #2 <- #192 DO ,1 SUB #3 <- #136 PLEASE ,1 SUB #4 <- #208 DO ,1 SUB #5 <- #98 DO COME FROM (1) DO READ OUT ,1 (2) DO ,1 SUB #1 <- #134 (1) PLEASE ABSTAIN FROM (2)

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Haxe

Haxe

var i = 1024; while (i > 0) { Sys.println(i); i >>= 1; }

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#hexiscript

hexiscript

let i 1024 while i > 0 println i let i (i / 2) endwhile

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#GML

GML

for(i = 10; i >= 0; i -= 1) show_message(string(i))

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Go

Go

for i := 10; i >= 0; i-- { fmt.Println(i) }

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#Ela

Ela

open monad io loop n | n % 6 == 0 = do return () | else = do putStrLn (show n) loop (n+1) _ = loop 10 ::: IO

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#COBOL

COBOL

IDENTIFICATION DIVISION. PROGRAM-ID. Display-Triangle. DATA DIVISION. WORKING-STORAGE SECTION. 01 Outer-Counter PIC 9. 01 Inner-Counter PIC 9. PROCEDURE DIVISION. PERFORM VARYING Outer-Counter FROM 1 BY 1 UNTIL 5 < Outer-Counter PERFORM VARYING Inner-Counter FROM 1 BY 1 UNTIL Outer-Counter < Inner-Counter DISPLAY "*" NO ADVANCING END-PERFORM DISPLAY "" *> Output a newline END-PERFORM GOBACK .

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Euphoria

Euphoria

for i = 1 to 10 by 2 do ? i end for

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lisaac

Lisaac

Section Header + name := LOOP_AND_HALF; Section Public - main <- ( + i : INTEGER; i := 1; { i.print; i = 10 }.until_do { ", ".print; i := i + 1; }; '\n'.print; );

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#LiveCode

LiveCode

repeat with n = 1 to 10 put n after loopn if n is not 10 then put comma after loopn end repeat put loopn

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Logo

Logo

make "a mdarray [10 10] for [j 1 10] [for [i 1 10] [mdsetitem list :i :j :a (1 + random 20)]] to until.20 for [j 1 10] [ for [i 1 10] [ type mditem list :i :j :a type "| | if equal? 20 mditem list :i :j :a [stop] ] print "|| ] end until.20

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lua

Lua

t = {} for i = 1, 20 do t[i] = {} for j = 1, 20 do t[i][j] = math.random(20) end end function exitable() for i = 1, 20 do for j = 1, 20 do if t[i][j] == 20 then return i, j end end end end print(exitable())

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#min

min

(1 2 3) 'puts foreach

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#MiniScript

MiniScript

for i in collection print i end

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#Haskell

Haskell

import Data.Char (digitToInt) luhn = (0 ==) . (`mod` 10) . sum . map (uncurry (+) . (`divMod` 10)) . zipWith (*) (cycle [1,2]) . map digitToInt . reverse

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#REXX

REXX

/*REXX pgm uses the Lucas─Lehmer primality test for prime powers of 2 (Mersenne primes)*/ @.=0; @.2=1; @.3=1; @.5=1; @.7=1; @.11=1; @.13=1 /*a partial list of some low primes. */ !.=@.; !.0=1; !.2=1; !.4=1; !.5=1; !.6=1; !.8=1 /*#'s with these last digs aren't prime*/ parse arg limit . /*obtain optional arguments from the CL*/ if limit=='' then limit= 200 /*Not specified? Then use the default.*/ say center('Mersenne prime index list',70-3,"═") /*show a fancy─dancy header (or title).*/ say right('M'2, 25) " [1 decimal digit]" /*left─justify them to align&look nice.*/ /* [►] note that J==1 is a special case*/ do j=1 by 2 to limit /*there're only so many hours in a day.*/ power= j + (j==1) /*POWER ≡ J except for when J=1. */ if \isPrime(power) then iterate /*if POWER isn't prime, then ignore it.*/ $= LL2(power) /*perform the Lucas─Lehmer 2 (LL2) test*/ if $=='' then iterate /*Did it flunk LL2? Then skip this #.*/ say right($, 25) MPsize /*left─justify them to align&look nice.*/ end /*j*/ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ isPrime: procedure expose !. @. /*allow 2 stemmed arrays to be accessed*/ parse arg x '' -1 z /*obtain variable X and last digit.*/ if @.x then return 1 /*is X already found to be a prime? */ if !.z then return 0 /*is last decimal digit even or a five?*/ if x//3==0 then return 0 /*divisible by three? Then not a prime*/ if x//7==0 then return 0 /*divisible by seven? " " " " */ do j=11 by 6 until j*j > x /*ensures that J isn't divisible by 3. */ if x // j ==0 then return 0 /*Is X divisible by J ? */ if x // (j+2)==0 then return 0 /* " " " " J+2 ? ___ */ end /*j*/ /* [↑] perform DO loop through √ x */ @.x=1; return 1 /*indicate number X is a prime. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ LL2: procedure expose MPsize; parse arg ? /*Lucas─Lehmer test on 2**? - 1 */ if ?==2 then s=0 /*handle special case for an even prime*/ else s=4 /* [↓] same as NUMERIC FORM SCIENTIFIC*/ numeric form; q= 2**? /*ensure correct form for REXX numbers.*/ /*╔═══════════════════════════════════════════════════════════════════════════╗ ╔═╝ Compute a power of 2 using only 9 decimal digits. One million digits ║ ║ could be used, but that really slows up computations. So, we start with the║ ║ default of 9 digits, and then find the ten's exponent in the product (2**?),║ ║ double it, and then add 6. {2 is all that's needed, but 6 is a lot ║ ║ safer.} The doubling is for the squaring of S (below, for s*s). ╔═╝ ╚═══════════════════════════════════════════════════════════════════════════╝*/ if pos('E', q)\==0 then do /*is number in exponential notation ? */ parse var q 'E' tenPow /*get the exponent. */ numeric digits tenPow * 2 + 6 /*expand precision. */ end /*REXX used dec FP. */ else numeric digits digits() * 2 + 6 /*use 9*2 + 6 digits*/ q=2**? - 1 /*compute a power of two, minus one. */ r= q // 8 /*obtain Q modulus eight. */ if r==1 | r==7 then nop /*before crunching, do a simple test. */ else return '' /*modulus Q isn't one or seven. */ do ?-2; s= (s*s -2) // q /*lather, rinse, repeat ··· */ end /* [↑] compute and test for a MP. */ if s\==0 then return '' /*Not a Mersenne prime? Return a null.*/ sz= length(q) /*obtain number of decimal digs in MP. */ MPsize=' ['sz "decimal digit"s(sz)']' /*define a literal to display after MP.*/ return 'M'? /*return "modified" # (Mersenne index).*/ /*──────────────────────────────────────────────────────────────────────────────────────*/ s: if arg(1)==1 then return arg(3); return word(arg(2) 's', 1) /*simple pluralizer*/

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Io

Io

loop("SPAM" println)

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#J

J

(-[smoutput bind 'SPAM')^:_(1)

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#HolyC

HolyC

U16 i = 1024; while (i > 0) { Print("%d\n", i); i /= 2; }

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Icon_and_Unicon

Icon and Unicon

procedure main() local i i := 1024 while write(0 < (i := i / 2)) end

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Groovy

Groovy

for (i in (10..0)) { println i }

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#Elixir

Elixir

defmodule Loops do def do_while(n) do n1 = n + 1 IO.puts n1 if rem(n1, 6) == 0, do: :ok, else: do_while(n1) end end Loops.do_while(0)

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#ColdFusion

ColdFusion

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#F.23

F#

for i in 2..2..8 do printf "%d, " i printfn "done"

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Logo

Logo

to comma.list :n repeat :n-1 [type repcount type "|, |] print :n end comma.list 10

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Lua

Lua

for i = 1, 10 do io.write(i) if i == 10 then break end io.write", " end

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#M2000_Interpreter

M2000 Interpreter

Module Checkit { Dim A(10,10)<<Random(1, 20) For k=1 to 2 { For i=0 to 9 { For j=0 to 9 { Print A(i,j) if A(i,j)=20 then goto there } } there: Print "...ok", k } } Checkit

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Maple

Maple

(m,n) := LinearAlgebra:-Dimensions(M): for i from 1 to m do for j from 1 to n do print(M[i,j]); if M[i,j] = 20 then (i,j):=m,n; next; end if; end do; end do:

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#MOO

MOO

things = {"Apple", "Banana", "Coconut"}; for thing in (things) player:tell(thing); endfor

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Nanoquery

Nanoquery

for item in collection println item end

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#HicEst

HicEst

CHARACTER numbers="49927398716 49927398717 1234567812345678 1234567812345670 " DO nr = 1, 4 EDIT(Text=numbers, ITeM=nr, Parse=number) sum_odds = 0 sum_even = 0 DO i = LEN(number), 1, -2 sum_odds = sum_odds + ICHAR(number(i)) - 48 IF(i > 1) THEN even2 = 2 * (ICHAR(number(i-1)) - 48) sum_even = sum_even + MOD(even2, 10) + INT(even2/10) ENDIF ENDDO valid = (0 == MOD(sum_odds + sum_even, 10)) WRITE() number, " is ", "invalid"(1 + 2*valid:) ENDDO

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#Ring

Ring

see "Mersenne Primes :" + nl for p = 2 to 18 if lucasLehmer(p) see "M" + p + nl ok next func lucasLehmer p i = 0 mp = 0 sn = 0 if p = 2 return true ok if (p and 1) = 0 return false ok mp = pow(2,p) - 1 sn = 4 for i = 3 to p sn = pow(sn,2) - 2 sn -= (mp * floor(sn / mp)) next return (sn=0)

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Java

Java

while (true) { System.out.println("SPAM"); }

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#JavaScript

JavaScript

for (;;) console.log("SPAM");

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Inform_7

Inform 7

let N be 1024; while N > 0: say "[N][line break]"; let N be N / 2;

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#IWBASIC

IWBASIC

DEF X:INT X=1024 OPENCONSOLE WHILE X>0 PRINT X X=X/2 ENDWHILE 'Output starts with 1024 and ends with 1. 'Putting the following in the loop will produce output starting with 512 and ending with 0: 'X=X/2 'PRINT X 'When compiled as a console only program, a press any key to continue message is automatic. 'I presume code is added by the compiler. CLOSECONSOLE 'Since this is, in fact, an IWBASIC console program, which compiles and runs. END

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Harbour

Harbour

FOR i := 10 TO 0 STEP -1 ? i NEXT

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Haskell

Haskell

import Control.Monad main :: IO () main = forM_ [10,9 .. 0] print

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#Emacs_Lisp

Emacs Lisp

(let ((val 0)) (while (progn (setq val (1+ val)) (message "%d" val) (/= 0 (mod val 6)))))

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#Common_Lisp

Common Lisp

(loop for i from 1 upto 5 do (loop for j from 1 upto i do (write-char #\*)) (terpri))

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Factor

Factor

1 10 2 <range> [ . ] each

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#M2000_Interpreter

M2000 Interpreter

Module Checkit { \\ old type loop For i=1 to 10 Print i; If i=10 Then Exit For Print ", "; Next i Print \\ fast type loop. Continue exit block, without breaking loop. For i=1 to 10 { Print i; If i=10 Then Continue Print ", "; } Print Print i=0 { loop \\ this mark block for loop, each time need to mark i++ Print i; If i=10 Then Exit ' so now we use exit to break loop Print ", "; } Print } Checkit

http://rosettacode.org/wiki/Loops/N_plus_one_half

Loops/N plus one half

Quite often one needs loops which, in the last iteration, execute only part of the loop body. Goal Demonstrate the best way to do this. Task Write a loop which writes the comma-separated list 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 using separate output statements for the number and the comma from within the body of the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#M4

M4

define(`break', `define(`ulim',llim)') define(`for', `ifelse($#,0,``$0'', `define(`ulim',$3)`'define(`llim',$2)`'ifelse(ifelse($3,`',1, `eval($2<=$3)'),1, `pushdef(`$1',$2)$4`'popdef(`$1')$0(`$1',incr($2),ulim,`$4')')')') for(`x',`1',`', `x`'ifelse(x,10,`break',`, ')')

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Mathematica.2FWolfram_Language

Mathematica/Wolfram Language

Do[ Print[m[[i, j]]]; If[m[[i, j]] === 20, Return[]], {i, 1, Dimensions[m][[1]]}, {j, 1, Dimensions[m][[2]]}]

http://rosettacode.org/wiki/Loops/Nested

Loops/Nested

Show a nested loop which searches a two-dimensional array filled with random numbers uniformly distributed over [ 1 , … , 20 ] {\displaystyle [1,\ldots ,20]} . The loops iterate rows and columns of the array printing the elements until the value 20 {\displaystyle 20} is met. Specifically, this task also shows how to break out of nested loops. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#MATLAB_.2F_Octave

MATLAB / Octave

a = ceil(rand(100,100)*20); [ix,iy]=find(a==20,1)

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Nemerle

Nemerle

def things = ["Apple", "Banana", "Coconut"]; foreach (thing in things) WriteLine(thing.ToLower()); foreach (i in [5, 10 .. 100]) Write($"$i\t");

http://rosettacode.org/wiki/Loops/Foreach

Loops/Foreach

Loop through and print each element in a collection in order. Use your language's "for each" loop if it has one, otherwise iterate through the collection in order with some other loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#NetRexx

NetRexx

/* NetRexx */ options replace format comments java crossref savelog symbols nobinary say say 'Loops/Foreach' days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'] daysl = Arrays.asList(days) daysi = daysl.iterator loop while daysi.hasNext say daysi.next end

http://rosettacode.org/wiki/Luhn_test_of_credit_card_numbers

Luhn test of credit card numbers

The Luhn test is used by some credit card companies to distinguish valid credit card numbers from what could be a random selection of digits. Those companies using credit card numbers that can be validated by the Luhn test have numbers that pass the following test: Reverse the order of the digits in the number. Take the first, third, ... and every other odd digit in the reversed digits and sum them to form the partial sum s1 Taking the second, fourth ... and every other even digit in the reversed digits: Multiply each digit by two and sum the digits if the answer is greater than nine to form partial sums for the even digits Sum the partial sums of the even digits to form s2 If s1 + s2 ends in zero then the original number is in the form of a valid credit card number as verified by the Luhn test. For example, if the trial number is 49927398716: Reverse the digits: 61789372994 Sum the odd digits: 6 + 7 + 9 + 7 + 9 + 4 = 42 = s1 The even digits: 1, 8, 3, 2, 9 Two times each even digit: 2, 16, 6, 4, 18 Sum the digits of each multiplication: 2, 7, 6, 4, 9 Sum the last: 2 + 7 + 6 + 4 + 9 = 28 = s2 s1 + s2 = 70 which ends in zero which means that 49927398716 passes the Luhn test Task Write a function/method/procedure/subroutine that will validate a number with the Luhn test, and use it to validate the following numbers: 49927398716 49927398717 1234567812345678 1234567812345670 Related tasks SEDOL ISIN

#Icon_and_Unicon

Icon and Unicon

procedure main(aL) every write(i := !aL ," - ", ((\isluhn10(i),"valid")|"invalid") \ 1) end procedure isluhn10(i) #: isluhn10(i) returns i (if i passes luhn10) or fails local sum sum :=0 reverse(integer(i)) ? while not pos(0) do { sum +:= move(1) sum +:= map(move(1),"0123456789","0246813579") } return (sum % 10 = 0,i) end

http://rosettacode.org/wiki/Lucas-Lehmer_test

Lucas-Lehmer test

Lucas-Lehmer Test: for p {\displaystyle p} an odd prime, the Mersenne number 2 p − 1 {\displaystyle 2^{p}-1} is prime if and only if 2 p − 1 {\displaystyle 2^{p}-1} divides S ( p − 1 ) {\displaystyle S(p-1)} where S ( n + 1 ) = ( S ( n ) ) 2 − 2 {\displaystyle S(n+1)=(S(n))^{2}-2} , and S ( 1 ) = 4 {\displaystyle S(1)=4} . Task Calculate all Mersenne primes up to the implementation's maximum precision, or the 47th Mersenne prime (whichever comes first).

#RPL

RPL

%%HP: T(3)A(R)F(.); ; ASCII transfer header \<< DUP LN DUP \pi * 4 SWAP / 1 + UNROT / * IP 2 { 2 } ROT 2 SWAP ; input n; n := Int(n/ln(n)*(1 + 4/(pi*ln(n)))), p:=2; (n ~ number of primes less then n, pi used here only as a convenience), 2 is assumed to be the 1st elemente in the list START SWAP NEXTPRIME DUP UNROT DUP 2 SWAP ^ 1 - 4 PICK3 2 - 1 SWAP ; for i := 2 to n, p := nextprime; s := 4; m := 2^p - 1; START SQ 2 - OVER MOD ; for j := 1 to p - 2; s := s^2 mod m; NEXT NIP NOT { + } { DROP } IFTE ; next j; if s = 0 then add p to the list else discard p; NEXT NIP ; next i; \>>

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Joy

Joy

DEFINE loop == [true []] dip while. ["SPAM\n" putchars] loop.

http://rosettacode.org/wiki/Loops/Infinite

Loops/Infinite

Task Print out SPAM followed by a newline in an infinite loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#jq

jq

recurse("SPAM")

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#J

J

,. <.@-:^:*^:a: 1024

http://rosettacode.org/wiki/Loops/While

Loops/While

Task Start an integer value at 1024. Loop while it is greater than zero. Print the value (with a newline) and divide it by two each time through the loop. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreachbas Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Java

Java

int i = 1024; while(i > 0){ System.out.println(i); i >>= 1; //also acceptable: i /= 2; }

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#Haxe

Haxe

class Step { var end:Int; var step:Int; var index:Int; public inline function new(start:Int, end:Int, step:Int) { this.index = start; this.end = end; this.step = step; } public inline function hasNext() return step > 0 ? end >= index : index >= end; public inline function next() return (index += step) - step; } class Main { static function main() { for (i in new Step(10, 0, -1)) { Sys.print('$i '); } } }

http://rosettacode.org/wiki/Loops/Downward_for

Loops/Downward for

Task Write a for loop which writes a countdown from 10 to 0. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#hexiscript

hexiscript

for let i 10; i >= 0; i-- println i endfor

http://rosettacode.org/wiki/Loops/Do-while

Loops/Do-while

Start with a value at 0. Loop while value mod 6 is not equal to 0. Each time through the loop, add 1 to the value then print it. The loop must execute at least once. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference Do while loop Wikipedia.

#Erlang

Erlang

do() -> do(0). do(0) -> io:fwrite( "0 " ), do( 1 ); do(N) when N rem 6 =:= 0 -> io:format("~w~n", [N]); do(N) -> io:fwrite( "~p ", [N] ), do(N+1).

http://rosettacode.org/wiki/Loops/For

Loops/For

“For” loops are used to make some block of code be iterated a number of times, setting a variable or parameter to a monotonically increasing integer value for each execution of the block of code. Common extensions of this allow other counting patterns or iterating over abstract structures other than the integers. Task Show how two loops may be nested within each other, with the number of iterations performed by the inner for loop being controlled by the outer for loop. Specifically print out the following pattern by using one for loop nested in another: * ** *** **** ***** Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges Reference For loop Wikipedia.

#Coq

Coq

Section FOR. Variable T : Type. Variable body : nat -> T -> T. Variable start : nat. Fixpoint for_loop n : T -> T := match n with | O => fun s => s | S n' => fun s => for_loop n' (body (start + n') s) end. End FOR. Eval vm_compute in for_loop _ (fun i => cons (for_loop _ (fun j => cons tt) 0 (S i) nil ) ) 0 5 nil.

http://rosettacode.org/wiki/Loops/For_with_a_specified_step

Loops/For with a specified step

Task Demonstrate a for-loop where the step-value is greater than one. Related tasks Loop over multiple arrays simultaneously Loops/Break Loops/Continue Loops/Do-while Loops/Downward for Loops/For Loops/For with a specified step Loops/Foreach Loops/Increment loop index within loop body Loops/Infinite Loops/N plus one half Loops/Nested Loops/While Loops/with multiple ranges Loops/Wrong ranges

#FALSE

FALSE

2[$9\>][$.", "2+]#"who do we appreciate!"