// create a number N of child processes specified via commandline argument
// each child sleeps for a random time between 1 and 5 seconds
// each child prints its PID and the time it slept
// the parent waits for all children to finish and then exits

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

int main(int argc, char *argv[]) {
    if (argc != 2) {
        fprintf(stderr, "Usage: %s <number of children>\n", argv[0]);
        return 1;
    }

    int n = atoi(argv[1]);

    for (int i = 0; i < n; i++) {
        pid_t pid = fork();
        if (pid < 0) {
            perror("fork");
            return 1;
        }

        if (pid == 0) {
            // child
            srand(getpid());
            int sleep_time = 1 + rand() % 5;
            printf("Child %d with PID %d will sleep for %d seconds\n", i, getpid(), sleep_time);
            sleep(sleep_time);
            printf("Child %d with PID %d slept for %d seconds\n", i, getpid(), sleep_time);
            return 0;
        }
    }

    // parent
    for (int i = 0; i < n; i++) {
        int status;
        wait(&status);
    }

    return 0;
}