#include <iostream>
#include <pthread.h>
#include <unistd.h>

using namespace std;

// A demo of pthreads.

#define NUM_THREADS 4

// print a countdown
void *countdown(void* arg) {

  int thread_id = *((int*) arg);

  cout << "started thread " << thread_id << endl;

  for (int count = 0; count <= 10; count++) {
    sleep(1); // sleep for 1 second
    cout << "thread " << thread_id << ": " << count << endl;
  }

  cout << "finished thread " << thread_id << endl;
  return NULL;
}

// create a set of threads to run simultaneous countdowns
int main() {

  cout << "main thread starting" << endl;

  pthread_t threads[NUM_THREADS]; // array of thread objects

  // create threads
  for (int tid = 0; tid < NUM_THREADS; tid++) {

    // create a thread and have it execute the countdown function
    if (pthread_create(&threads[tid], NULL, countdown, &tid)) {
      cout << "Error creating thread" << endl;
    }

    usleep(200000); // sleep for 200 ms
  }

  // wait for threads to finish
  for (int tid = 0; tid < NUM_THREADS; tid++) {
    /*
    if (pthread_join(threads[tid], NULL)) {
      cout << "Error joining thread" << endl;
    }
    */
  }

  cout << "main thread exiting" << endl;

  return 0;
}