如何使两个线程在一个线程结束后轮流执行各自的临界区

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

std::mutex mtx;
std::condition_variable cv;
bool isTurnA = true;

void threadA()
{
    std::unique_lock<std::mutex> lock(mtx);
    for (int i = 0; i < 5; ++i)
    {
        while (!isTurnA)
        {
            cv.wait(lock);
        }
        // 线程A的临界区操作
        std::cout << "Thread A executing..." << std::endl;
        isTurnA = false;
        cv.notify_one();
    }
}

void threadB()
{
    std::unique_lock<std::mutex> lock(mtx);
    for (int i = 0; i < 5; ++i)
    {
        while (isTurnA)
        {
            cv.wait(lock);
        }
        // 线程B的临界区操作
        std::cout << "Thread B executing..." << std::endl;
        isTurnA = true;
        cv.notify_one();
    }
}

int main()
{
    std::thread tA(threadA);
    std::thread tB(threadB);
    tA.join();
    tB.join();
    return 0;
}