C++ std::shared_mutex读写锁的使用

#include <iostream>
//std::unique_lock
#include <mutex> 
#include <shared_mutex>
#include <thread>
 
class ThreadSafeCounter {
public:
    ThreadSafeCounter() = default;
 
    // 多个线程/读者能同时读计数器的值。
    unsigned int get() const {
        std::shared_lock<std::shared_mutex> lock(mutex_);
        return value_;
    }
 
    // 只有一个线程/写者能增加/写线程的值。
    void increment() {
        std::unique_lock<std::shared_mutex> lock(mutex_);
        value_++;
    }
 
    // 只有一个线程/写者能重置/写线程的值。
    void reset() {
        std::unique_lock<std::shared_mutex> lock(mutex_);
        value_ = 0;
    }
 
private:
    mutable std::shared_mutex mutex_;
    unsigned int value_ = 0;
};
 
int main() {
    ThreadSafeCounter counter;
 
    auto increment_and_print = [&counter]() {
        for (int i = 0; i < 3; i++) {
            counter.increment();
            std::cout << std::this_thread::get_id() << '\t' << counter.get() << std::endl;
        }
    };
 
    std::thread thread1(increment_and_print);
    std::thread thread2(increment_and_print);
 
    thread1.join();
    thread2.join();
 
    system("pause");
    return 0;
}