#include <iostream> 
#include <unistd.h> 
#include <pthread.h> 
 
using std::cout; 
using std::cerr; 
using std::cin; 
using std::endl; 
 
// Must compile with -pthread 
 
struct Data 
{ 
   unsigned int num; 
   pthread_mutex_t mut; 
}; 
 
void * RunThread(void *ptr); 
 
int main() 
{ 
   unsigned int posInt = 1; 
   Data d; 
 
   void *pRtnValue; 
   pthread_t myThread; 
 
   d.num = 1; 
 
   pthread_mutex_init(&d.mut, NULL); 
 
   pthread_create(&myThread, NULL, RunThread, &d); 
 
   while(posInt) 
   { 
      cout << "Enter a positive integer:"; 
      cin >> posInt; 
      pthread_mutex_lock(&d.mut); 
      d.num = posInt; 
      pthread_mutex_unlock(&d.mut); 
      pthread_yield(); 
   } 
 
   /* Wait for the thread to quit */ 
   if(pthread_join(myThread, &pRtnValue) == 0) 
   { 
      cerr << "Thread terminated" << endl; 
   } 
   else 
   { 
      cerr << "Error on thread termination" << endl; 
   } 
 
   return 0; 
} 
 
void * RunThread(void *ptr) 
{ 
   Data *dataPtr = (Data*)ptr; 
   bool stillGoing = true; 
 
   while(stillGoing) 
   { 
      sleep(1); 
      pthread_mutex_lock(&dataPtr->mut); 
      if(dataPtr->num == 0) 
      { 
         stillGoing = false; 
      } 
      else 
      { 
         dataPtr->num++;  
         cout << "                           " << dataPtr->num << endl; 
      } 
      pthread_mutex_unlock(&dataPtr->mut); 
      pthread_yield(); 
   } 
 
   pthread_exit(ptr); 
}