//
// Wrote for Computer Networks and Systems lab classes
// AUTHOR : Sergiusz Warga

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

void parent_before_child() {
    pid_t pid;
    printf("parent_before_child()\n");
    pid = fork();
    if (pid == -1) {    // If something went wrong.
        perror("Fork: ");
        exit(EXIT_FAILURE);
    }
    if (pid != 0) {     // If this is a parent process.
        printf("I am a parent.\n");
        kill(getpid(), SIGKILL);
    } else {
        sleep(1);
        printf("I am a child\n");   // This line will not be printed, as (usually) parent process will finish
        // its execution in less than 1 second.
    }
}

void child_before_parent() {
    pid_t pid;
    printf("child_before_parent()\n");
    pid = fork();
    if (pid == -1) {    // If something went wrong.
        perror("Fork: ");
        exit(EXIT_FAILURE);
    }
    if (pid == 0) {     // If this is a parent process.
        printf("I am a child.\n");
        kill(getpid(), SIGKILL);
    } else {
        sleep(1);
        printf("I am a parent.\n");
    }
}

int main() {
    pid_t pid;
    pid = fork();
    if (pid == 0) {
        child_before_parent();
        sleep(1);
        parent_before_child();
        sleep(1);
    }
    sleep(5);
    return 0;
}