/*
  main2.cc
  This is a simple test program that will demonstrate how
  problems may arise in concurrent programming.

*/

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

// Declare a global int that will cause us all sorts of problems

int counter = 0;

void* Thread_1(void* Argument);
void* Thread_2(void* Argument);

int main()
{

  pthread_t first_thread, second_thread;

  pthread_create(&first_thread, NULL, Thread_1, NULL);
  pthread_create(&second_thread, NULL, Thread_2, NULL);

  pthread_join(first_thread, NULL);
  pthread_join(second_thread, NULL);

  cout<<"counter is:"<<counter<<endl;

  return 0;
}

void* Thread_1(void* Argument)
{

  int i;

  for(int j = 0; j<20000; j++)
  {
    i = counter;
    i++;
    for(int k=0; k<5000 ; k++);	//delay for a while
    counter = i; 
    
  }

  return NULL;
  
}

void* Thread_2(void* Argument)
{

  int j;

  for(int i = 0; i<20000; i++)
  {

    j = counter;
    j++;
    for(int k=0; k<5000 ; k++);	//delay for a while
    counter = j;

  }

  return NULL;
  
}