代码

#include <iostream>
#include <utility>
#include <thread>
#include <chrono>
#include <functional>
#include <atomic>
 
void f1(int n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 1 executing\n";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}
 
void f2(int& n)
{
    for (int i = 0; i < 5; ++i) {
        std::cout << "Thread 2 executing\n";
        ++n;
        std::this_thread::sleep_for(std::chrono::milliseconds(10));
    }
}
 
int main()
{
    int n = 0;
    std::thread t1; // t1 非线程
    std::thread t2(f1, n + 1); // 按值传递
    std::thread t3(f2, std::ref(n)); // 按引用传递
    std::thread t4(std::move(t3)); // t4 现在运行 f2() 。 t3 不再是线程
    t2.join();
    t4.join();
    std::cout << "Final value of n is " << n << '\n';
}

评测结果