How to concat integer and string inside recursive function in C -

guys, want make program generate combination elements. example if user input (n) = 3, output must :

1 12 123 13 2 23 3 

i have problem concat integer , string inside recursive function..

code :

#include <stdio.h>  void rekursif(int m, int n, char angka[100]){     int i;     for(i=m; i<=n; i++){         sprintf(angka, "%s %d", angka, i);         printf("%s \n", angka);         rekursif(i+1,n,angka);     } }  int main(){     rekursif(1,5,"");     return 0; } 

when run program, command prompt not responding. guess, problem in concation ( sprintf(angka, "%s %d", angka, i); ) please me solve problem. thank :)

by passing "" function argument, trying modify string literal, undefined behavior. instead, do:

int main(){     char str[100];     rekursif(1, 5, str);     return 0; } 

be careful buffer overflow in practice.