/* 
 * Scrieti un program C (numit A) care creeaza un proces fiu B. Procesul B genereaza un numar aleator intre 100 si 1000. Procesul A genereaza cate un numar aleator intre 50 si 1050 si il trimite procesului B pana cand diferenta absoluta intre numarul generat de B si numarul trimis de A este mai mica decat 50. B afiseaza fiecare numar primit de la A. A va afisa la final numarul de numere generate pana cand conditia de oprire este indeplinita.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>

int main(int argc, char *argv[]) {
  int f, p2c[2], c2p[2];
  pipe(p2c);
  pipe(c2p);
  f = fork();
  if(f < 0) {
    perror("Error on fork");
    close(p2c[0]);
    close(p2c[1]);
    close(c2p[0]);
    close(c2p[1]);
    exit(1);
  } else if (f == 0) {
    close(p2c[1]);
    close(c2p[0]);
    srandom(getpid());
    int target = random() % 901 + 100;
    printf("The child process has generated target number %d\n", target);
    int received = 0;
    int found = 0;
    while(!found) {
      if(0 > read(p2c[0], &received, sizeof(int))) {
        perror("C --- Error reading number from pipe");
      }
      printf("The child process received %d from parent\n", received);
      if(abs(target - received) < 50) {
        found = 1;
        printf("Close enough\n");
      }
      if(0 > write(c2p[1], &found, sizeof(int))) {
        perror("C --- Error writing number to pipe");
      }
    }
    close(p2c[0]);
    close(c2p[1]);
    exit(0);
  }
  close(p2c[0]);
  close(c2p[1]);
  srandom(getpid());
  int guess = 0, found = 0, count = 0;
  while(!found) {
    count++;
    guess = random() % 1001 + 50;
    printf("Parent is guessing %d\n", guess);
    if(0 > write(p2c[1], &guess, sizeof(int))) {
      perror("P --- Error writing number to pipe");
    }
    if(0 > read(c2p[0], &found, sizeof(int))) {
      perror("P --- Error reading number from pipe");
    }
  }
  close(p2c[1]);
  close(c2p[0]);
  wait(0);
  printf("Parent guessed after %d tries\n", count);
  return 0;
}