在指定的时间段内运行函数：带有< chrono>的C ++； [英] Running a function for specified duration : C++ with <chrono>

问题描述

我需要实现一个函数，该函数应在指定的持续时间内执行指定的任务，并将其作为参数（std :: chrono :: milliseconds）传递给它。

I need to implement a function that should do specified task for specified duration which is passed to it as parameter (std::chrono::milliseconds).

我想出了代码：

void Run(std::chrono::milliseconds ms)
{
    std::chrono::time_point<std::chrono::system_clock> start, end;
    start = std::chrono::system_clock::now();
    std::chrono::duration<double> elapsed_seconds = end - start;
    while (elapsed_seconds <= (ms / 1000))
    {
        std::cout << "Running" << std::endl;
        end = std::chrono::system_clock::now();
        elapsed_seconds = end - start;
    }
}

int main()
{
    {
        std::chrono::milliseconds ms(30000);
        Run(ms);
        system("Pause");
    }

我想打印运行 30秒钟，然后退出。但是它没有这样做。如何使用 C ++< chrono>

I suppose the code to print Running for 30 seconds and then exit. But it does not do so. How do I achieve such behavior with C++ <chrono>

推荐答案

您真正需要做的就是知道 end 点，然后循环直到达到该点：

All you really need is to know the end point and then loop until that point is reached:

#include <chrono>

void Run(std::chrono::milliseconds ms)
{
    std::chrono::time_point<std::chrono::system_clock> end;

    end = std::chrono::system_clock::now() + ms; // this is the end point

    while(std::chrono::system_clock::now() < end) // still less than the end?
    {
        std::cout << "Running" << std::endl;
    }
}

int main()
{
    std::chrono::milliseconds ms(3000);
    Run(ms);
    system("Pause");
}

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