/* c99: VLAs, system with the concatenation of two strings */
 
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int my_system(char *s1, char *s2) {
  char s[strlen(s1) + 1 + strlen(s2) + 1];
  strcpy(s, s1);
  strcat(s, " ");
  strcat(s, s2);
  
  return system(s);
}

int main() {

  my_system("ls", "-l");
  
  return 0;
}