#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
//子進程讀數據
void read_data(int pipes[]) 
{
	int c;
	int rc;
	//關閉寫的一端
	close(pipes[1]);
	//讀數據并打印
	while ((rc = read(pipes[0], &c, 1)) > 0)
	{
		putchar(c);
	}
	exit(0);
}

//父進程寫數據
void write_data(int pipes[])
{
	int c;
	int rc;
	//關閉讀數據一端
	close(pipes[0]);
	//從控制臺讀數據并向管道寫數據
	while ((c = getchar()) > 0) 
	{
		rc = write(pipes[1], &c, 1);
		if (rc == -1)
		{
			perror("Parent: write");
			close(pipes[1]);
			exit(1);
		}
	}
	//關閉寫一端
	close(pipes[1]);
	exit(0);
}

int main(int argc, char*argv[])
{
	int pipes[2];
	pid_t pid;
	//fork返回的進程號
	int rc;
	//返回值
	//建立管道
	rc = pipe(pipes);
	if (rc == -1) 
	{
		perror("pipe");
		exit(1);
	}
	//建立子進程
	pid = fork();
	switch(pid)
	{
		//失敗
	case -1:
		perror("fork");
		exit(1);
		//子進程
	case 0:
		read_data(pipes);
		//不能到這里
		//父進程
	default:
		write_data(pipes);//不能到這里/
	}
	return 0;
}