#include <thread>

 #include <iostream>

 #include <mutex>

 #include <atomic>

 #include <chrono>

 using namespace std;

 #ifdef _LOCK_FREE

 atomic<int> i = ;

 void foo() {

     int count = ;

     while (count--)

     {

         i++;

     }

 }

 int main()

 {

     chrono::steady_clock::time_point start_time = chrono::steady_clock::now();

     thread thread1(foo);

     thread thread2(foo);

     thread1.join();

     thread2.join();

     cout << "i = " << i << endl;

     chrono::steady_clock::time_point end_time = chrono::steady_clock::now();

     chrono::duration<double> time_span = chrono::duration_cast<chrono::microseconds>(end_time - start_time);

     cout << "lock free elpased time: " << time_span.count() << " ms" << endl;

     system("pause");

     return ;

 }

 #endif // _LOCK_FREE

 #ifdef _MUTEX_LOCK

 int i = ;

 mutex g_mutex;

 void foo() {

     int count = ;

     while (count--)

     {

         g_mutex.lock();

         i++;

         g_mutex.unlock();

     }

 }

 int main()

 {

     chrono::steady_clock::time_point start_time = chrono::steady_clock::now();

     thread thread1(foo);

     thread thread2(foo);

     thread1.join();

     thread2.join();

     cout << "i = " << i << endl;

     chrono::steady_clock::time_point end_time = chrono::steady_clock::now();

     chrono::duration<double> time_span = chrono::duration_cast<chrono::microseconds>(end_time - start_time);

     cout << "mutex lock elpased time: " << time_span.count() << " ms" << endl;

     system("pause");

     return ;

 }

 #endif _MUTEX_LOCK