#include <iostream>
#include <thread>
#include <mutex>

using namespace std ;

mutex mtx ;

void thread_function1()
{
   for( int i1=0 ; i1<5 ; i1++ )
     {
	    // Pre C++ 11
	   //lock_guard<mutex> lk( mtx ) ;
	   //With C++ 17
	   lock_guard lk( mtx ) ;
       cout << "Thread function1: " << i1 << endl ;

     }

}



int main()
{
    thread t1( &thread_function1 );   // t1 starts running
    //cout << "main thread\n";

    // main thread waits for the thread t1 to finish
    t1.join();



    return 0;
}