Repeat a string

Repeat a string
You are encouraged to solve this task according to the task description, using any language you may know.

Take a string and repeat it some number of times. Example: repeat("ha", 5) => "hahahahaha"

Ada

In Ada multiplication of an universal integer to string gives the desired result. Here is an example of use: <lang Ada> with Ada.Strings.Fixed; use Ada.Strings.Fixed; with Ada.Text_IO; use Ada.Text_IO;

procedure String_Multiplication is begin

  Put_Line (5 * "ha");

end String_Multiplication; </lang> Sample output:

hahahahaha

C

<lang c>

1. include <stdio.h>
2. include <stdlib.h>
3. include <string.h>

char * string_repeat( int n, const char * s ) {

 size_t slen = strlen(s);
 char * dest = (char *)calloc(n*slen, sizeof(char));

 int i; char * p;
 for ( i=0, p = dest; i < n; ++i, p += slen ) {
   memcpy(p, s, slen);
 }
 return dest;

}

int main() {

 printf("%s\n", string_repeat(5, "ha"));

}

</lang>

C++

<lang cpp>#include <string>

1. include <iostream>

std::string repeat( const std::string &word, int times ) {

  std::string result ;
  result.reserve(times*word.length()); // avoid repeated reallocation
  for ( int a = 0 ; a < times ; a++ ) 
     result += word ;
  return result ;

}

int main( ) {

  std::cout << repeat( "Ha" , 5 ) << std::endl ;
  return 0 ;

}</lang>

C#

<lang csharp> String s = "".PadLeft(5, 'X').Replace("X", "ha")</lang>

Clojure

<lang clojure>(apply str (apply concat (repeat 5 "ha")))</lang>

E

<lang e>"ha" * 5</lang>

Forth

<lang forth>

place-n { src len dest n -- }

 0 dest c!
 n 0 ?do src len dest +place loop ;

create test 256 allot s" ha" test 5 place-n test count type \ hahahahaha </lang>

Fortran

Works with: Fortran version 90 and later

<lang fortran>program test_repeat

 write (*, '(a)') repeat ('ha', 5)

end program test_repeat</lang> Output:

hahahahaha

Haskell

For a string of finite length:

<lang haskell>concat $ replicate 5 "ha"</lang>

For an infinitely long string:

<lang haskell>cycle "ha"</lang>

J

<lang j>

  5 ((* #) $ ]) 'ha'

hahahahaha </lang>

Java

Works with: Java version 1.5+

There's no function or operator to do this in Java, so you have to do it yourself. <lang java5>public static String repeat(String str, int times){

  StringBuilder ret = new StringBuilder();
  for(int i = 0;i < times;i++) ret.append(str);
  return ret.toString();

}

public static void main(String[] args){

 System.out.println(repeat("ha", 5));

}</lang>

Or even shorter: <lang java5>public static String repeat(String str, int times){

  return new String(new char[times]).replace("\0", str);

}</lang>

JavaScript

This solution creates an array of n+1 null elements, then joins them using the target string as the delimiter <lang javascript>String.prototype.repeat = function(n) {

   return new Array(1 + parseInt(n, 10)).join(this);

}

alert("ha".repeat(5)); // hahahahaha</lang>

Logo

<lang logo> to copies :n :thing [:acc "||]

 if :n = 0 [output :acc]
 output (copies :n-1 :thing combine :acc :thing)

end </lang> or using cascade: <lang logo> show cascade 5 [combine "ha ?] "||  ; hahahahaha </lang>

OCaml

<lang ocaml>let string_repeat s n =

 let len = String.length s in
 let res = String.create(n * len) in
 for i = 0 to pred n do
   String.blit s 0 res (i * len) len;
 done;
 (res)

</lang>

testing in the toplevel: <lang ocaml># string_repeat "Hiuoa" 3 ;; - : string = "HiuoaHiuoaHiuoa"</lang>

Alternately: <lang ocaml>let string_repeat s n =

 String.concat "" (Array.to_list (Array.make n s))

</lang>

Or: <lang ocaml>let string_repeat s n =

 Array.fold_left (^) "" (Array.make n s)

</lang>

Perl

<lang perl>"ha" x 5</lang>

Perl 6

Works with: Rakudo version #21 "Seattle"

<lang perl6>"ha" x 5</lang>

(Note that the x operator isn't quite the same as in Perl 5: it now only creates strings. To create lists, use xx.)

PHP

<lang php>str_repeat("ha", 5)</lang>

PowerBASIC

<lang powerbasic>MSGBOX REPEAT$(5, "ha")</lang>

Pure

str_repeat is defined by pattern-matching: repeating any string 0 times results in the empty string; while repeating it more than 0 times results in the concatenation of the string and (n-1) further repeats.

<lang pure> > str_repeat 0 s = ""; > str_repeat n s = s + (str_repeat (n-1) s) if n>0; > str_repeat 5 "ha"; "hahahahaha" > </lang>

Python

<lang python>"ha" * 5 # ==> "hahahahaha"</lang>

Ruby

<lang ruby>"ha" * 5 # ==> "hahahahaha"</lang>

Scala

<lang scala>"ha" * 5 // ==> "hahahahaha"</lang>

Tcl

<lang tcl>string repeat "ha" 5  ;# => hahahahaha</lang>