/*
  pipe1.c++ creates a pipe and parent-child 
            communicates through it.
*/
#include <iostream>
using namespace std;
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>

int main() { // pipe1.c++
      int chpid, fd[2], err, status ;

      err = pipe(fd) ;
      if(err == -1) {
         cerr << "pipe open error\n" ;
         return 0;
      }
      chpid = fork();
      if(chpid == -1){
        cerr << "fork() error\n";
        return 0;
      }
      if(chpid > 0){ // write in parent
         char buffP[100] = "IIIT Kalyani";
         close(fd[0]);
         write(fd[1], buffP, strlen(buffP));
         cout << "Parent has written in pipe\n"; 
         close(fd[1]);
         waitpid(chpid, &status,0); 
      }
      else { // child
         char buffC[100]={0};
        
         close(fd[1]);
         sleep(5);         
         read(fd[0], buffC, 100);
         cout << "Child: " << buffC << endl;
         close(fd[0]);
      }
      return 0;
}