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

int main () {
  int pipe1[2]; // Parent to child
  int pipe2[2]; // Child to parent

  // Create both pipes
  if (pipe(pipe1) == -1 || pipe(pipe2) == -1) {
    fprintf(stderr, "Could not open pipes");
    return 1;
  }

  // Fork process
  pid_t pid = fork();

  if (pid == 0) {
    // Child process

    // Close unused pipe ends
    close(pipe1[1]) ; // Close write end of pipe1
    close(pipe2[0]) ; // Close read end of pipe2

    // Read message, send response
    char *message = malloc(100);
    read(pipe1[0], message, 100);
    printf("%s", message);
    free(message);

    char response[] = "Response from child to parent\n";
    write(pipe2[1], response, sizeof(response));
  } else {
    // Parent process

    // Close unused pipe ends
    close(pipe1[0]) ; // Close read end of pipe1
    close(pipe2[1]) ; // Close write end of pipe2

    // Send message, read response
    char message[] = "Sending message from parent to child\n";
    write(pipe1[1], message, sizeof(message));

    char *response = malloc(100);
    read(pipe2[0], response, 100);
    printf("%s", response);
    free(response);

    // Wait for child process to terminate
    waitpid(pid, NULL, 0);
  }

  return 0;
}