//
//  CPE334
//  PROBLEM SESSION 1: Process Creation & Pipes
//  Created by Warat Kaweepornpoj on 1/24/2560 BE.
//  57070501038
//

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

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

    int fd[2];
    pid_t child_pid, pid;
    char send[30], recv[30];

    pipe(fd);
    child_pid = fork();
    pid = getpid();

    // Problem 1 - Hello from Child

    if(child_pid==0){
        printf("Parent %d\n", pid);
        read(fd[0], &recv, sizeof(recv));
        printf("%s\n", recv);

    } else {
        sprintf(send, "Hello from %d", pid);
        write(fd[1], &send, strlen(send)+1);
        printf("Child %d\n", pid);
    }

    close(fd[0]);
    close(fd[1]);


    // Problem 2 - Hello from Parent

    if(child_pid==0){
        printf("Parent %d\n", pid);
        sprintf(send, "Hello from %d", pid);
        write(fd[1], &send, strlen(send)+1);

    } else {
        printf("Child %d\n", pid);
        read(fd[0], &recv, sizeof(recv));
        printf("%s\n", recv);
    }

    close(fd[0]);
    close(fd[1]);

    return 0;
}