#include <string.h>
#include <time.h>
#include <iostream>
#include <string>
#include <vector>
#include <thread>
#include <mutex>
#include <atomic>
using namespace std;
mutex g_lock;
string str(1024, 'A');
struct spin_lock {
    static void lock() {
        while (lock_.test_and_set(std::memory_order_acquire)) {
        }
    }
    static void unlock() {
        lock_.clear();
    }
    static atomic_flag lock_;
};
atomic_flag spin_lock::lock_ = ATOMIC_FLAG_INIT;
void fun(int i) {
    for (int loop = 0;loop < 100000;loop++) {
    lock_guard<mutex>lk(g_lock); // 0.635s
//  spin_lock().lock();          // 0.636s
    if (i % 2) {
        str = "123";
    }
    else {
        str = "456";
    }
    spin_lock().unlock();
    }
}
int main() {
    int n = 10;
    srand(time(0));
    vector<thread>threads;
    for (int i = 0;i < n;i++) {
        threads.emplace_back(thread(fun, i));
    }
    for (auto &th : threads) {
        th.join();
    }

    return 0;
}