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

/* Try this variant also, and estimate the number of lines printed. */
/* void f ( int n )
{
   int i;

   for (i=n-1; i>=1; --i) {
      if (!fork()) {
         printf("Hi %d, %d, n = %d, i = %d\n", getppid(), getpid(), n, i);
         fflush(stdout);
         f(i);
         if (n % 3 == 1) return;
      }
   }
} */

void f ( int n )
{
   int i;

   for (i=n-1; i>=1; --i) {
      if (!fork()) {
         printf("Hi %d, %d, n = %d, i = %d\n", getppid(), getpid(), n, i);
         fflush(stdout);
         f(i);
         return;
      }
   }
}

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

   n = (argc > 1) ? atoi(argv[1]) : 4;
   f(n);
   usleep(1000);

   exit(0);
}