controller

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <sys/stat.h>
 #include <unistd.h>

#define BUFSIZE 256

main()
{
    int c1p[2]; //pipe to link c1 to c2
    int c1pid;  //parent ID
    int c1status;

    int c2p[2]; //pipe
    int c2pid;  //parent ID
    int c2status;

    int c3p[2]; //pipe
    int c3pid;  //parent ID
    int c3status;


    int len;
    char buffer[BUFSIZE];
    int read_len;

    pipe(c1p);



    c1pid = fork();
    if (c1pid == 0) {
        int newfd = 1;
        newfd = dup2(c1p[1],newfd);
        if (newfd != 1)
        {
            fprintf(stderr,"unable to duplicate newfd \n");
            exit(1);
        }
        close(c1p[0]);
        execvp("./c1", NULL);


    } else {
        c1pid = wait(&c2status);
        printf("process 2 finished \n");
    }

    pipe(c2p);

    c2pid = fork();
    if (c2pid == 0) {
        int newfd = 1;
        newfd = dup2(c2p[1],newfd);
        if (newfd != 1)
        {
            fprintf(stderr,"unable to duplicate newfd \n");
            exit(1);
        }
        close(c2p[0]);
        execvp("./c2", NULL);


    } else {
        c2pid = wait(&c2status);
        printf("process 2 finished \n");
    }
}