/* File:  ~liux/public_html/courses/cop4610/examples/simple-pipe.cc
   Purpose: Demonstrate how to use pipes to communicate between
            parent and child processes 
   Author:  Xiuwen Liu, 
   On the web: 
     http://www.cs.fsu.edu/~liux/courses/cop4610/examples/simple-pipe.cc
   Compile:
     g++ -o simple-pipe simple-pipe.cc
*/

#include <sys/types.h>
#include <strings.h>
#include <sys/wait.h>
#include <signal.h>
#include <stdio.h>
#include <unistd.h>
#include <iostream.h>
#define  MAXLINE  512

int main(void)
{
  int n, fd[2];
  pid_t  pid;
  char   line[MAXLINE];
  
  
  if (pipe(fd) < 0) {
    perror("pipe");
    return -1;
  }
  
  if ( (pid = fork()) < 0) {
    cerr << "Counld not create new process." << endl;
    perror("fork");
    return -1;
  }
  else {
    if (pid ==0) { /* Child */
      close(fd[1]);
      n=read(fd[0], line, MAXLINE);
      line[n]='\0';
      cout << "Child received: " << line;
      close(fd[0]);
    }
    else { /* Parent */
      close(fd[0]);
      write(fd[1],"Hello, world!\n",strlen("Hello, world!\n"));
      close(fd[1]);
    }
  }
  return 0;
}