#include "sys/types.h"
#include "sys/file.h"
#include "sys/wait.h"
#include "unistd.h"
#include <cstdio>
#include <cstdlib>
#include <cstring>

char r_buf[4];
char w_buf[4];
int pipe_fd[2];
pid_t pid1, pid2, pid3, pid4;

int producer(int id);
int consumer(int id);

int main(int argc, char **argv) {
    if (pipe(pipe_fd) < 0) {
        printf("pipe create error \n");
        exit(-1);
    } else {
        printf("pipe is created successfully!\n");
        if ((pid1 = fork()) == 0) producer(1);
        if ((pid2 = fork()) == 0) producer(2);
        if ((pid3 = fork()) == 0) consumer(1);
        if ((pid4 = fork()) == 0) consumer(2);
    }
    close(pipe_fd[0]);
    close(pipe_fd[1]);
    int i, pid, status;
    for (i = 0; i < 4; i++)
        pid = wait(&status);
    exit(0);
}

int producer(int id) {
    printf("producer %d is running!\n", id);
    close(pipe_fd[0]);
    int i = 0;
    for (i = 1; i < 10; i++) {
        sleep(3);
        if (id == 1)
            strcpy(w_buf, "aaa\0");
        else
            strcpy(w_buf, "bbb\0");
        if (write(pipe_fd[1], w_buf, 4) == -1)
            printf("write to pipe error\n");
    }
    close(pipe_fd[1]);
    printf("producer %d is over!\n", id);
    exit(id);
}

int consumer(int id) {
    close(pipe_fd[1]);
    printf("consumer %d is running!\n", id);
    if (id == 1)
        strcpy(w_buf, "ccc\0");
    else
        strcpy(w_buf, "ddd\0");
    while (1) {
        sleep(1);
        strcpy(r_buf, "eee\0");
        if (read(pipe_fd[0], r_buf, 4) == 0)
            break;
        printf("consumer %d get %s, while the w_buf is %s\n", id, r_buf, w_buf);
    }
    close(pipe_fd[0]);
    printf("consumer %d is over!\n", id);
    exit(id);
}