// A demonstration of unix pipes where the output of the parent
// program is redirected to the input of a child
#include <iostream>
#include <unistd.h>

using namespace std;

void parent_main();
void child_main();

int main(void) {
  int p[2];
  int i;
  int pid;

  //create the pipe
  pipe(p);

  //fork the process
  pid = fork();

  //set up the pipe
  if(pid) {
    //parent process does the writing
    dup2(p[1], STDOUT_FILENO);

    //close the unused side of the pipe
    close(p[0]);

    parent_main();
  } else {
    //child process does the reading
    dup2(p[0], STDIN_FILENO);
    
    //close the unused side of the pipe
    close(p[1]);

    child_main();
  }


  return 0;
}



void 
parent_main() {
  for(int i=0; i<10; i++) {
    cout << i << endl;
  }
}

void 
child_main() {
  //read the entire input stream
  int i;
  while(cin >> i) {
    cout << "Child received: " << i << endl;
  }

}