#include <stdlib.h>
#include <unistd.h>
#include <stdio.h>
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
int main(int argc, char *argv[]) {
    int p2c[2], c2p[2];
    if (0 > pipe(p2c)) {
        perror("Error on pipe p2c");
        exit(1);
    }
    if (0 > pipe(c2p)) {
        perror("Error on pipe c2p");
        exit(1);
    }
    int f = fork();
    if (0 > f) {
        perror("Error on fork");
        exit(1);
    } else if (0 == f) {
        close(p2c[1]);
        close(c2p[0]);
        int n;
        while(1) {
            if (0 > read(p2c[0], &n, sizeof(int))) {
                perror("Error on child read");
            }
            printf("Child received %d\n", n);
            n /= 2;
            printf("Child sending %d\n", n);
            if (0 > write(c2p[1], &n, sizeof(int))) {
                perror("Error on child write");
            }
            if(n < 5)
                break;
        }
        close(p2c[0]);
        close(c2p[1]);
        exit(0);
    } else {
        close(p2c[0]);
        close(c2p[1]);
        srandom(time(NULL));
        int n = random() % 151 + 50;
        printf("Parent generated %d\n", n);
        while(n >= 5) {
            if(n % 2 == 1)
                n++;
            printf("Parent sending %d\n", n);
            if (0 > write(p2c[1], &n, sizeof(int))) {
                perror("Error on parent write");
            }

            if (0 > read(c2p[0], &n, sizeof(int))) {
                perror("Error on parent read");
            }
            printf("Parent received %d\n", n);
        }
        wait(0);
        close(p2c[1]);
        close(c2p[0]);
    }
    return 0;
}