Question

Suppose that you have three programs that are suppose to print a house diagram in a collaborative manner.

(i) prog1.c

#include <stdio.h>      /* Input/Output */

#include <stdlib.h>     /* General Utilities */

int main()

{

    printf(“                      ^^^^^^^^^^^^                       \n”);

    printf(“           ^^^^^^^^^^^            ^^^^^^^^^^^            \n”);

    printf(“^^^^^^^^^^^                                  ^^^^^^^^^^^ \n”);

    printf(“     |                                            |      \n”);

    printf(“     |                                            |      \n”);

    exit(1);

}

(i) prog2.c

#include <stdio.h>      /* Input/Output */

#include <stdlib.h>     /* General Utilities */

int main()

{

    printf(“     |                                             |     \n”);

    printf(“     |                                             |     \n”);

    printf(“     |     ^^^^^^^^^^^            ^^^^^^^^^^^      |     \n”);

    printf(“     |     ^         ^            ^         ^      |     \n”);

    printf(“     |     ^         ^            ^         ^      |     \n”);

    printf(“     |     ^         ^            ^         ^      |     \n”);

    exit(1);

}

(i) prog3.c

#include <stdio.h>      /* Input/Output */

#include <stdlib.h>     /* General Utilities */

int main()

{

    printf(“     |     ^          ^           ^         ^      |     \n”);

    printf(“     |     ^          ^           ^         ^      |     \n”);

    printf(“     |     ^          ^           ^         ^      |     \n”);

    printf(“     |     ^^^^^^^^^^^            ^^^^^^^^^^^      |     \n”);

    printf(“     |                                             |     \n”);

    printf(“     |                                             |      \n”);

    printf(“     ______________________________________________      \n”);                                                                                            |      \n");

    exit(1);

}

Fill out the following c program (name it as house1.c) that draws a 1-story house diagram correctly. Your program should use the following system calls:

• fork()
• any variant of the exec class system calls
• waitpid()

You have to remember prog1.c, prog2.c and prog3.c should be executed in a specific order in a synchronized manner, i.e., prog2 initiates its execution after prog1 is finished and prog3 should be initiated after prog2 is finished!

Note1: prog1, prog2, and prog3 should be executed by children processes. Parent process should not execute any of these.

Note2: Exception handling should be done when any of the system calls fails such as fork(), execl(), etc.

#include<sys/types.h>

#include<sys/wait.h>

#include<unistd.h>

#include<stdio.h>

#include<stdlib.h>

int main()

{

    pid_t pid1;

    pid_t pid2;

    int status;

    pid1 = -1;

    pid2 = -1;

    pid1 = fork();

    pid2 = fork();

    if (pid1 == 0 && pid2 == 0)

    {

       // Fill out this part!

    }

    if ( pid1 == 0 && pid2 > 0)

    {

       // Fill out this part!

    }

    if ( pid1 > 0 && pid2 ==0)

    {

         // Fill out this part!

    }

    if ( pid1 >0 && pid2 > 0)

    {

         // Fill out this part!

    }

}

Answer 1