#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
	
int
main(void)
{
	int	n, fd[2];
	pid_t	pid;
	char	line[64];

	if (pipe(fd) < 0) {
		perror("pipe error");
		exit(1);
	}

	if ( (pid = fork()) < 0) {
		perror("fork error");
		exit(1);
	}

	else if (pid > 0) {		/* parent */
		snprintf(line, 64, "Hello child!  I'm your parent pid %d!\n", getpid());
		close(fd[0]);
		write(fd[1], line, strlen(line));

	} else {				/* child */
		close(fd[1]);
		n = read(fd[0], line, 64);
		write(STDOUT_FILENO, line, n);
		printf("I'm the child(%d).\n", getpid());
	}

	exit(0);
}