Repeat

The task is to write a procedure which accepts as arguments another procedure and a positive integer. The latter procedure is executed a number of times equal to the accepted integer.

Repeat is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

C

<lang C>

1. include <stdio.h>

void repeat(void (*f)(void), int n) {

for(int i=n; 0<i; i--)
(*f)();

}

void example() {

printf("Example\n");

}

void main(char *argv[], int argc) {

repeat(example, 4);

} </lang>

Haskell

<lang Haskell> rep :: Monad m => m () -> Integer -> m () rep _ 0 = return () rep f n = f >> rep f (n-1)

sampleFunction :: IO () sampleFunction = putStrLn "a"

main = rep sampleFunction 5 </lang>

Python

<lang Python>

1. !/usr/bin/python

def repeat(f,n):

 for i in range(n):
   f();

def procedure():

 print("Example");

repeat(procedure,3); #prints "Example" (without quotes) three times, separated by newlines. </lang>

Racket

The racket guide has a section called "Iterators and Comprehensions", which shows that for isn't just for repeating n times!

I'm not smart enough to do the Captcha, so here's some of the URL: docs.racket-lang.org/guide/for.html?q=iterators

<lang Racket>#lang racket/base (define (repeat f n) ; the for loop is idiomatic of (although not exclusive to) racket

 (for ((_ n)) (f)))

(define (repeat2 f n) ; This is a bit more "functional programmingy"

 (when (positive? n) (f) (repeat2 f (sub1 n))))

(display "...") (repeat (λ () (display " and over")) 5) (display "...") (repeat2 (λ () (display " & over")) 5) (newline)</lang>

Output:

... and over and over and over and over and over... & over & over & over & over & over