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

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


int main() {
    int pipefd[2];
    if (pipe(pipefd) < 0){
    	fprintf(stderr,"Something went wrong!\n");
    	return -1;
    }
	
	int in = 42;
	int out = 0;
	int status;
	pid_t pid;
    pid = fork();

    if (pid == -1) {    // If something went wrong.
        perror("Fork: ");
        exit(EXIT_FAILURE);
    }

    if (pid == 0) {     // If this is a child process.
        read(pipefd[0], &out, sizeof(out));
        printf("%d\n", out);
        close(pipefd[0]);
        exit(EXIT_SUCCESS);
    }

	write(pipefd[1], &in, sizeof(in));
	
	wait(&status);
	close(pipefd[1]);
	
	return 0;
}