lock free

#include <thread>
#include <iostream>
#include <mutex>
#include <atomic>
#include <chrono>

using namespace std;

#ifdef _LOCK_FREE

atomic<int> i = 0;

void foo() {
    int count = 10000000;
    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 0;
}
#endif // _LOCK_FREE



#ifdef _MUTEX_LOCK
int i = 0;
mutex g_mutex;


void foo() {
    int count = 10000000;
    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 0;
}
#endif _MUTEX_LOCK