#include <stdio.h>
#include <stdlib.h>
#include <pthread.h>
#include <iostream>

using std::cout;
using std::cerr;
using std::endl;

//A global variable accessible to all threads.
int thread_count;

void* Hello(void* rank);    /* The function for each thread to run */

int main(int argc, char** argv) {
    pthread_t* thread_handles;

    //get the number of threads from the command line
    if (argc != 2) {
        cerr << "Error, usage: " << endl;
        cerr << "    " << argv[0] << " <number of threads>" << endl;
        exit(1);
    }

   thread_count = atol(argv[1]);

//   thread_handles = malloc(thread_count * sizeof(pthread_t));
   thread_handles = new pthread_t[thread_count];

   long thread;
   for (thread = 0; thread < thread_count; thread++) {
       pthread_create(&thread_handles[thread], NULL, Hello, (void*)thread);
   }

//   cout << "Hello from the main thread" << endl;
    printf("Hello from the main thread!\n");

   for (thread = 0; thread < thread_count; thread++) {
       pthread_join(thread_handles[thread], NULL);
   }

   free(thread_handles);
   return 0;
}

void* Hello(void* rank) {
    long my_rank = (long)rank;

    cout << "Hello from thread " << my_rank << " of " << thread_count << endl;
    printf("Hello from thread %ld of %d\n", my_rank, thread_count);
}