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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
#Make
Make
NEXT=`expr $* + 1` MAX=10 RES=1   all: 1-n;   $(MAX)-n: @echo $(RES)   %-n: @-make -f loop.mk $(NEXT)-n MAX=$(MAX) RES=$(RES),$(NEXT)
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
#Maxima
Maxima
data: apply(matrix, makelist(makelist(random(100), 20), 20))$   find_value(a, x) := block( [p, q], [p, q]: matrix_size(a), catch( for i thru p do for j thru q do if a[i, j] = x then throw([i, j]), 'not\ found ) )$   find_value(data, 100); not found
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
#NewLISP
NewLISP
(map println '(Apple Banana Coconut))
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
#Nim
Nim
let list = ["lorem", "ipsum", "dolor"} for item in list: echo item
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
#IS-BASIC
IS-BASIC
100 PROGRAM "CredCard.bas" 110 DO 120 PRINT :PRINT "Credit card number:":INPUT PROMPT ">":CCN$ 130 IF CCN$="" THEN EXIT DO 140 IF LUHN(TRIM$(CCN$)) THEN 150 PRINT "Card number is valid." 160 ELSE 170 SET #102:INK 3:PRINT "Card number is invalid.":SET #102:INK 1 180 END IF 190 LOOP 200 DEF LUHN(CCN$) 210 LET L=LEN(CCN$):LET S=0 220 FOR I=1 TO L 230 LET N=VAL(CCN$(L-I+1)) 240 IF I BAND 1 THEN 250 LET S=S+N 260 ELSE 270 LET N=N*2:LET S=S+MOD(N,10)+INT(N/10) 280 END IF 290 NEXT 300 LET LUHN=MOD(S,10)=0 310 END DEF 320 DEF TRIM$(S$) 330 LET T$="" 340 FOR I=1 TO LEN(S$) 350 IF S$(I)>CHR$(47) AND S$(I)<CHR$(58) THEN LET T$=T$&S$(I) 360 NEXT 370 LET TRIM$=T$ 380 END DEF
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).
#Ruby
Ruby
def is_prime ( p ) return true if p == 2 return false if p <= 1 || p.even? (3 .. Math.sqrt(p)).step(2) do |i| return false if p % i == 0 end true end   def is_mersenne_prime ( p ) return true if p == 2 m_p = ( 1 << p ) - 1 s = 4 (p-2).times { s = (s ** 2 - 2) % m_p } s == 0 end   precision = 20000 # maximum requested number of decimal places of 2 ** MP-1 # long_bits_width = precision / Math.log(2) * Math.log(10) upb_prime = (long_bits_width - 1).to_i / 2 # no unsigned # upb_count = 45 # find 45 mprimes if int was given enough bits #   puts " Finding Mersenne primes in M[2..%d]:" % upb_prime   count = 0 for p in 2..upb_prime if is_prime(p) && is_mersenne_prime(p) print "M%d " % p count += 1 end break if count >= upb_count end puts
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
#Jsish
Jsish
for (;;) puts('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
#Julia
Julia
  while true println("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
#JavaScript
JavaScript
var n = 1024; while (n > 0) { print(n); 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
#Joy
Joy
DEFINE putln == put '\n putch.   1024 [] [dup putln 2 /] while.
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
#HicEst
HicEst
DO i = 10, 0, -1 WRITE() i ENDDO
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
#HolyC
HolyC
I8 i; for (i = 10; i >= 0; --i) Print("%d\n", 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.
#ERRE
ERRE
  A=0 REPEAT A=A+1 PRINT(A) UNTIL A MOD 6=0  !UNTIL A-6*INT(A/6)=0 for C-64  
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.
#Euphoria
Euphoria
  include std/console.e include std/math.e   atom x = 0   loop do x += 1 ?x until(mod(x,6)) = 0 end loop   if getc(0) then end if  
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.
#Cowgol
Cowgol
include "cowgol.coh";   var i: uint8 := 1; while i <= 5 loop var j: uint8 := 1; while j <= i loop print_char('*'); j := j + 1; end loop; print_nl(); i := i + 1; end loop;
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
#Fantom
Fantom
  class Main { public static Void main () { Int step := 5 for (Int i := 0; i < 100; i += step) { echo (i) } } }  
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
#Maple
Maple
> for i to 10 do printf( "%d%s", i, `if`( i = 10, "\n", ", " ) ) end: 1, 2, 3, 4, 5, 6, 7, 8, 9, 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
#Mathematica.2FWolfram_Language
Mathematica/Wolfram Language
i = 1; s = ""; While[True, s = s <> ToString@i; If[i == 10, Break[]]; s = s <> ","; i++; ] s
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
#MAXScript
MAXScript
  fn scan_Nested arr = ( for subArray in arr where classof subArray == Array do ( for item in subArray do ( print item as string if item == 20 do return OK ) ) )  
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
#Objeck
Objeck
fruits := ["Apple", "Banana", "Coconut"]; each(i : fruits) { fruits[i]->PrintLine(); };
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
#Objective-C
Objective-C
NSArray *collect; //... for(Type i in collect){ NSLog(@"%@", i); }
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
#J
J
luhn=: 0 = 10 (| +/@,) 10 #.inv 1 2 *&|: _2 "."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).
#Rust
Rust
    extern crate rug; extern crate primal;   use rug::Integer; use rug::ops::Pow; use std::thread::spawn;   fn is_mersenne (p : usize) { let p = p as u32; let mut m = Integer::from(1); m = m << p; m = Integer::from(&m - 1); let mut flag1 = false; for k in 1..10_000 { let mut flag2 = false; let mut div : u32 = 2*k*p + 1; if &div >= &m {break; } for j in [3,5,7,11,13,17,19,23,29,31,37].iter() { if div % j == 0 { flag2 = true; break; } } if flag2 == true {continue;} if div % 8 != 1 && div % 8 != 7 { continue; } if m.is_divisible_u(div) { flag1 = true; break; } } if flag1 == true {return ()} let mut s = Integer::from(4); let two = Integer::from(2); for _i in 2..p { let mut sqr = s.pow(2); s = Integer::from(&Integer::from(&sqr & &m) + &Integer::from(&sqr >> p)); if &s >= &m {s = s - &m} s = Integer::from(&s - &two); } if s == 0 {println!("Mersenne : {}",p);} }   fn main () { println!("Mersenne : 2"); let limit = 11_214; let mut thread_handles = vec![]; for p in primal::Primes::all().take_while(|p| *p < limit) { thread_handles.push(spawn(move || is_mersenne(p))); } for handle in thread_handles { handle.join().unwrap(); } }  
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
#K
K
while[1; `0:"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
#Kotlin
Kotlin
// version 1.0.6   fun main(args: Array<String>) { while (true) println("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
#jq
jq
# To avoid printing 0, test if the input is greater than 1 1024 | recurse( if . > 1 then ./2 | floor else empty 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
#Jsish
Jsish
#!/usr/bin/env jsish /* Loops/While in Jsish */ var i = 1024;   while (i > 0) { puts(i); i = i / 2 | 0; }   /* =!EXPECTSTART!= 1024 512 256 128 64 32 16 8 4 2 1 =!EXPECTEND!= */
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
#Icon_and_Unicon
Icon and Unicon
every i := 10 to 0 by -1 do { # things to do within the loop }  
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
#IDL
IDL
for i=10,0,-1 do print,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.
#F.23
F#
  let rec loop n = printfn "%d " n if (n+1)%6 > 0 then loop (n+1) loop 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.
#Crystal
Crystal
  1.upto(5) do |i| 1.upto(i) do |j| print "*" end puts end  
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
#FBSL
FBSL
#APPTYPE CONSOLE   DIM n AS INTEGER FOR n = 2 TO 8 STEP 2 PRINT n; IF n < 8 THEN PRINT " "; NEXT PRINT ", who will we obliterate?" PAUSE  
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
#MATLAB_.2F_Octave
MATLAB / Octave
printf('%i, ',1:9); printf('%i\n',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
#MAXScript
MAXScript
for i in 1 to 10 do ( format "%" i if i == 10 then exit format "%" ", " )
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
#Microsoft_Small_Basic
Microsoft Small Basic
For row = 0 To 10 For col = 0 To 10 array[row][col] = Math.GetRandomNumber(20) EndFor EndFor For row = 0 To 10 For col = 0 To 10 TextWindow.WriteLine("row "+row+" col "+col+" value "+array[row][col]) If array[row][col] = 20 Then Goto exit_for_row EndIf EndFor EndFor exit_for_row:
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
#MOO
MOO
a = make(10, make(10)); for i in [1..10] for j in [1..10] a[i][j] = random(20); endfor endfor for i in [1..10] s = ""; for j in [1..10] s += tostr(" ", a[i][j]); if (a[i][j] == 20) break i; endif endfor player:tell(s); s = ""; endfor player:tell(s);
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
#OCaml
OCaml
List.iter (fun i -> Printf.printf "%d\n" i) collect_list
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
#Octave
Octave
a = [ 1,4,3,2 ]; b = [ 1,2,3,4; 5,6,7,8 ]; for v = a disp(v); % output single values: 1,4,3,2 endfor for v = b disp(v); % v is the column vector [1;5], then [2;6] ... endfor
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
#Java
Java
public class Luhn { public static void main(String[] args) { System.out.println(luhnTest("49927398716")); System.out.println(luhnTest("49927398717")); System.out.println(luhnTest("1234567812345678")); System.out.println(luhnTest("1234567812345670")); }   public static boolean luhnTest(String number){ int s1 = 0, s2 = 0; String reverse = new StringBuffer(number).reverse().toString(); for(int i = 0 ;i < reverse.length();i++){ int digit = Character.digit(reverse.charAt(i), 10); if(i % 2 == 0){//this is for odd digits, they are 1-indexed in the algorithm s1 += digit; }else{//add 2 * digit for 0-4, add 2 * digit - 9 for 5-9 s2 += 2 * digit; if(digit >= 5){ s2 -= 9; } } } return (s1 + s2) % 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).
#Scala
Scala
object LLT extends App { import Stream._   def primeSieve(s: Stream[Int]): Stream[Int] = s.head #:: primeSieve(s.tail filter { _ % s.head != 0 }) val primes = primeSieve(from(2))   def mersenne(p: Int): BigInt = (BigInt(2) pow p) - 1   def s(mp: BigInt, p: Int): BigInt = { if (p == 1) 4 else ((s(mp, p - 1) pow 2) - 2) % mp }   val upbPrime = 9941 println(s"Finding Mersenne primes in M[2..$upbPrime]") ((primes takeWhile (_ <= upbPrime)).par map { p => (p, mersenne(p)) } map { p => if (p._1 == 2) (p, 0) else (p, s(p._2, p._1 - 1)) } filter { _._2 == 0 }) .foreach { p => println(s"prime M${(p._1)._1}: " + { if ((p._1)._1 < 200) (p._1)._2 else s"(${(p._1)._2.toString.size} digits)" }) } println("That's All Folks!") }
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
#LabVIEW
LabVIEW
  {def loops_infinite {lambda {} {if true then SPAM{br} {loops_infinite} else never}}} -> loops_infinite   {loops_infinite} -> SPAM forever...  
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
#Lambdatalk
Lambdatalk
  {def loops_infinite {lambda {} {if true then SPAM{br} {loops_infinite} else never}}} -> loops_infinite   {loops_infinite} -> SPAM forever...  
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
#Julia
Julia
  n = 1024   while n > 0 println(n) n >>= 1 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
#K
K
  {while[x>0; \echo x; x%:2]} 1024  
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
#Inform_6
Inform 6
for(i = 10: i >= 0: i--) 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
#Io
Io
for(i,10,0,-1, i println )
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.
#Factor
Factor
0 [ dup 6 mod 0 = not ] [ [ . ] [ 1 + ] bi ] do while drop
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.
#D
D
import std.stdio: write, writeln;   void main() { for (int i; i < 5; i++) { for (int j; j <= i; j++) write("*"); writeln(); } writeln();   foreach (i; 0 .. 5) { foreach (j; 0 .. i + 1) write("*"); writeln(); } }
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
#Fermat
Fermat
for i = 1 to 100 by 13 do !i;!' '; od
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
#Metafont
Metafont
last := 10; string s; s := ""; for i = 1 upto last: s := s & decimal i; if i <> last: s := s & ", " fi; endfor message s; end
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
#Microsoft_Small_Basic
Microsoft Small Basic
For i = 1 To 10 TextWindow.Write(i) If i <> 10 Then TextWindow.Write(", ") EndIf EndFor TextWindow.WriteLine("")
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
#MUMPS
MUMPS
NESTLOOP  ;.../loops/nested  ;set up the 2D array with random values NEW A,I,J,K,FLAG,TRIGGER SET K=15 ;Magic - just to give us a size to work with SET TRIGGER=20 ;Magic - the max value, and the end value FOR I=1:1:K FOR J=1:1:K SET A(I,J)=$RANDOM(TRIGGER)+1  ;Now, search through the array, halting when the value of TRIGGER is found SET FLAG=0 SET (I,J)=0 FOR I=1:1:K Q:FLAG W ! FOR J=1:1:K WRITE A(I,J),$SELECT(J'=K:", ",1:"") SET FLAG=(A(I,J)=TRIGGER) Q:FLAG KILL A,I,J,K,FLAG,TRIGGER QUIT
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
#Neko
Neko
/** Loops/Nested in Neko Tectonics: nekoc loops-nested.neko neko loops-nested.neko */   var random = $loader.loadprim("std@random_new", 0)(); var random_int = $loader.loadprim("std@random_int", 2);   var values = $amake(10); var row = 0; var col = 0;   while row < 10 { values[row] = $amake(10); col = 0; while col < 10 { values[row][col] = random_int(random, 20) + 1; col += 1; } row += 1; }   /* Look for a 20 */ /* To break out of nested loops, (without using labels and $goto), Neko needs the value of the inner loop(s). The break statement sets the return value of a loop expression. Without a break, the value of a loop expression is unspecified. */ var inner; row = 0; while row < 10 { col = 0; inner = while col < 10 { $print("values[", row, "][", col, "] = ", values[row][col], "\n"); if values[row][col] == 20 break true; col += 1; } if $istrue(inner) break; row += 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
#Oforth
Oforth
: printMonths | m | Date.Months forEach: m [ m . ] ;
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
#Ol
Ol
  (for-each print '(1 3 4 2)) (print) (for-each (lambda (a b c) (print a "-" b "/" c)) '(1 2 3 4) '(5 6 7 8) '(a b x z))  
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
#JavaScript
JavaScript
mod10check = function(cc) { return $A(cc).reverse().map(Number).inject(0, function(s, d, i) { return s + (i % 2 == 1 ? (d == 9 ? 9 : (d * 2) % 9) : d); }) % 10 == 0; }; ['49927398716','49927398717','1234567812345678','1234567812345670'].each(function(i){alert(mod10check(i))});
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).
#Scheme
Scheme
;;;The heart of the algorithm (define (S n) (let ((m (- (expt 2 n) 1))) (let loop ((c (- n 2)) (a 4)) (if (zero? c) a (loop (- c 1) (remainder (- (* a a) 2) m))))))   (define (mersenne-prime? n) (if (= n 2) #t (zero? (S n))))   ;;;Trivial unoptimized implementation for the base primes (define (next-prime x) (if (prime? (+ x 1)) (+ x 1) (next-prime (+ x 1))))   (define (prime? x) (let loop ((c 2)) (cond ((>= c x) #t) ((zero? (remainder x c)) #f) (else (loop (+ c 1))))))   ;;Main loop (let loop ((i 45) (p 2)) (if (not (zero? i)) (if (mersenne-prime? p) (begin (display "M") (display p) (display " ") (loop (- i 1) (next-prime p))) (loop i (next-prime p)))))
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
#Lang5
Lang5
do "SPAM\n" . 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
#Lasso
Lasso
// not wise to run this! while(1 > 0) => {^ 'SPAM\r' ^}
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
#Kotlin
Kotlin
// version 1.0.6   fun main(args: Array<String>) { var value = 1024 while (value > 0) { println(value) value /= 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
#LabVIEW
LabVIEW
  {def loops_while {lambda {:i} {if {< :i 1} then (end of loop) else :i {loops_while {/ :i 2}}}}} -> loops_while   {loops_while 1024} -> 1024 512 256 128 64 32 16 8 4 2 1 (end of loop)  
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
#J
J
,. i. -11
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
#Java
Java
  for (int i = 10; i >= 0; i--) { System.out.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.
#Fantom
Fantom
  class Main { public static Void main () { i := 0 while (true) { i += 1 echo (i) if (i % 6 == 0) break // end loop on condition } } }  
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.
#Forth
Forth
: do-until 0 begin 1+ dup . dup 6 mod 0= until drop ;
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.
#Dao
Dao
for( i = 1 : 5 ){ for( j = 1 : i ) io.write( '*' ) io.writeln() }
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
#FOCAL
FOCAL
FOR I = 1,3,10; TYPE I, !
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
#min
min
1 (dup 10 ==) 'puts! (print succ ", " print!) () linrec
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
#Modula-3
Modula-3
MODULE Loop EXPORTS Main;   IMPORT IO, Fmt;   VAR i := 1;   BEGIN LOOP IO.Put(Fmt.Int(i)); IF i = 10 THEN EXIT; END; IO.Put(", "); i := i + 1; END; IO.Put("\n"); END Loop.
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
#Nemerle
Nemerle
using System; using System.Console; using Nemerle.Imperative;   module NestedLoops { Main() : void { def arr = array(10, 10); def rnd = Random();   foreach ((i, j) in $[(i, j) | i in [0 .. 9], j in [0 .. 9]]) arr[i, j] = rnd.Next(1, 21);   Finish: { foreach ((i, j) in $[(i, j) | i in [0 .. 9], j in [0 .. 9]]) { Write("{0} ", arr[i, j]); when (arr[i, j] == 20) Finish(); } } } }
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
#ooRexx
ooRexx
/* Rexx */ say say 'Loops/Foreach' out = ''   days = .array~of('Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday')   loop daysi over days out ||= daysi' ' end daysi say out~strip()   exit
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
#Oz
Oz
declare MyList = [1 2 3 4] in {ForAll MyList Show}   %% or: for E in MyList do {Show E} 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
#jq
jq
def luhn: def odds: . as $in | reduce range(0; length) as $i ([]; if ($i % 2) == 0 then . + [$in[$i]] else . end); def evens: . as $in | reduce range(1; length) as $i ([]; if ($i % 2) == 1 then . + [$in[$i]] else . end); def digits: map([.]|implode|tonumber); def sumdigits: tostring | explode | digits | add;   (tostring | explode | reverse ) as $reverse | ($reverse | odds | digits | add) as $s1 | ($reverse | evens | digits | map(. * 2 | sumdigits) | add) as $s2 | 0 == ($s1 + $s2) % 10 ;
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).
#Scilab
Scilab
iexpmax=30 n=1 for iexp=2:iexpmax if iexp==2 then s=0; else s=4; end n=(n+1)*2-1 for i=1:iexp-2 s=modulo((s*s-2),n) end if s==0 then printf("M%d ",iexp); end end
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
#Liberty_BASIC
Liberty BASIC
  while 1 print "SPAM" wend end  
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
#Lily
Lily
  while 1: print("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
#Lambdatalk
Lambdatalk
  {def loops_while {lambda {:i} {if {< :i 1} then (end of loop) else :i {loops_while {/ :i 2}}}}} -> loops_while   {loops_while 1024} -> 1024 512 256 128 64 32 16 8 4 2 1 (end of loop)  
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
#Lang5
Lang5
: /i / int ; : 0= 0 == ; : dip swap '_ set execute _ ; : dupd 'dup dip ; : 2dip swap '_x set swap '_y set execute _y _x ; : while do dupd 'execute 2dip rot 0= if break else dup 2dip then loop ;   1024 "dup 0 >" "dup . 2 /i" while
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
#JavaScript
JavaScript
for (var i=10; i>=0; --i) 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
#jq
jq
range(10;-1;-1)
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.
#Fortran
Fortran
INTEGER :: i = 0 DO i = i + 1 WRITE(*, *) i IF (MOD(i, 6) == 0) EXIT END DO
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.
#Dart
Dart
main() { for (var i = 0; i < 5; i++) for (var j = 0; j < i + 1; j++) print("*"); print("\n"); }
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
#Forth
Forth
: test 9 2 do i . 2 +loop ." who do we appreciate?" cr ;
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
#MUMPS
MUMPS
LOOPHALF NEW I FOR I=1:1:10 DO .WRITE I .IF I'=10 WRITE ", " QUIT  ;Alternate NEW I FOR I=1:1:10 WRITE I WRITE:I'=10 ", " KILL I QUIT
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
#Nemerle
Nemerle
foreach (i in [1 .. 10]) { Write(i); unless (i == 10) Write(", "); }
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
#NetRexx
NetRexx
/* NetRexx */ options replace format comments java crossref savelog symbols nobinary   say say 'Loops/Nested'   rnd = Random() dim2 = int[10, 10]   -- build sample data loop i1 = 0 for dim2.length loop i2 = 0 for dim2[i1].length dim2[i1, i2] = rnd.nextInt(20) + 1 end i2 end i1   -- run test loop x1 = 0 for dim2.length say Rexx(x1 + 1).right(4)': \-' loop x2 = 0 for dim2[x1].length say Rexx(dim2[x1, x2]).right(3) || '\-' if dim2[x1, x2] = 20 then leave x1 finally say end x2 finally say end x1
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
#PARI.2FGP
PARI/GP
for(i=1,#v,print(v[i]))
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
#Pascal
Pascal
foreach my $i (@collection) { print "$i\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
#Julia
Julia
luhntest(x::Integer) = (sum(digits(x)[1:2:end]) + sum(map(x -> sum(digits(x)), 2 * digits(x)[2:2:end]))) % 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).
#Seed7
Seed7
$ include "seed7_05.s7i"; include "bigint.s7i";   const func boolean: isPrime (in integer: number) is func result var boolean: prime is FALSE; local var integer: upTo is 0; var integer: testNum is 3; begin if number = 2 then prime := TRUE; elsif number rem 2 = 0 or number <= 1 then prime := FALSE; else upTo := sqrt(number); while number rem testNum <> 0 and testNum <= upTo do testNum +:= 2; end while; prime := testNum > upTo; end if; end func;   const func boolean: lucasLehmerTest (in integer: p) is func result var boolean: prime is TRUE; local var bigInteger: m_p is 0_; var bigInteger: s is 4_; var integer: i is 0; begin if p <> 2 then m_p := 2_ ** p - 1_; for i range 2 to pred(p) do s := (s ** 2 - 2_) rem m_p; end for; prime := s = 0_; end if; end func;   const proc: main is func local var integer: p is 2; begin writeln(" Mersenne primes:"); while p <= 3217 do if isPrime(p) and lucasLehmerTest(p) then write(" M" <& p); flush(OUT); end if; incr(p); end while; writeln; end func;
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
#Lingo
Lingo
repeat while TRUE put "SPAM" end repeat
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
#Lisaac
Lisaac
{ "SPAM\n".print; }.endless_loop;
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
#Lambdatalk_2
Lambdatalk
  {def while {lambda {:i} {if {< :i 1} then else {br}:i {while {/ :i 2}}}}}   {while 1024} ->   1024 512 256 128 64 32 16 8 4 2 1  
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
#Julia
Julia
for i in 10:-1:0 println(i) 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
#Kotlin
Kotlin
  // version 1.3.61   fun main() { (10 downTo 0).forEach { println(it) } }  
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.
#Fortress
Fortress
  component loops_do_while export Executable   var x:ZZ32 = 0 run() = label loop while true do x += 1 println(x)   if (x MOD 6) = 0 then exit loop end end end loop end  
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.
#FreeBASIC
FreeBASIC
' FB 1.05. 0 Win64   Dim i As Integer = 0 Do i += 1 Print i; " "; Loop While i Mod 6 <> 0 Print Sleep
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.
#dc
dc
[ [*]P [print asterisk]sz lj 1 + d sj [increment j, leave it on stack]sz li !<A [continue loop if i >= j]sz ]sA [ 1 d sj [j = 1, leave it on stack]sz li !<A [enter loop A if i >= j]sz [ ]P [print newline]sz li 1 + d si [increment i, leave it on stack]sz 5 !<B [continue loop if 5 >= i]sz ]sB 1 d si [i = 1, leave it on stack]sz 5 !<B [enter loop B if 5 >= i]sz
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
#Fortran
Fortran
do i = 1,10,2 print *, i end do
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
#NetRexx
NetRexx
/* NetRexx */ /* NetRexx */ options replace format comments java crossref savelog symbols nobinary   say say 'Loops/N plus one half'   rs = '' istart = 1 iend = 10 loop i_ = istart to iend rs = rs || ' ' || i_ if i_ < iend then do rs = rs',' end end i_ say rs.strip()