/* Name : Edison Chindrawaly
 * File : parent2.c
 * Date : 03/06/01
 * Subj : It uses parent-child relationship to count
 *        the multiple of 5 and 3 for integer of 10000
 */

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>

int main()
{
 pid_t pid;
 int fd[2];
 int mul5 = 0;
 int mul3 = 0;
 int imul3 = 0;
 int terminate = -1; // terminating signal
 int isend = 0;
 int byte;

 if(pipe(fd) < 0)
   printf("pipe error\n");

 pid = fork(); // fork the process

 if(pid<0)
   printf("fork error\n");
 else if(pid > 0)
 {
   printf("I am parent\n");
   for(int i = 0; i < 10000; i++)
   {
     if((i%5) == 0)
       mul5++;
     else
       byte = write(fd[1], &i, sizeof(i)); //send to child     
   }
   write(fd[1], &terminate, sizeof(int));
   printf("Multiple of 5 counted by parent: %i \n", mul5);
   printf("Parent PID: %d \n", getpid());
   read(fd[0],&imul3,sizeof(int));
   printf("Multiple of 3 send by child: %i \n", imul3);
 }
 else
 { 
   printf("I am child\n");
   while( (byte=read(fd[0],&isend,sizeof(int)) != 0))
   {
     if(isend % 3 == 0)
       mul3++;
     if(isend == -1)
       break;
   }
   write(fd[1],&mul3,sizeof(int));
   printf("Child PID : %d\n", getpid());
   printf("Multiple of 3 counted by child in child: %i\n",mul3);
   exit(1);
 }
 exit(1);
}