Fork x number of child processes which have a set lifetime

fork.c

#include <stdio.h>
#include <stdlib.h>

static int expiry = 30;

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

  int k = *argv[1];
  int i=0;

  for(i = 0; i<k; i++){
    if(fork() == 0){ 
        printf("Forked child %d %d\n", i, ++k);
        sleep(expiry);
        printf("Forked child %d done\n",i);
        exit(0);
    }else{
        fprintf(stderr, "!! Unable to fork child: %d", i);
    }
  }

  return 0;
}