如何获取持续时间，如int毫秒和浮动秒从< chrono>？ [英] How to get duration, as int milli's and float seconds from <chrono>?

问题描述

我想要一个 Duration frameStart;

我想要使用chrono库来计算时间和持续时间。 code>（from app start）
和持续时间frameDelta; （帧间时间）

我需要能够得到 frameDelta 持续时间为毫秒和浮动秒。

这与新的c ++ 11 < chrono> 库？我一直在做它和谷歌（信息是稀疏）。

解决方案

代码是非常模板化的，需要特殊的转换和事情，我不知道如何正确使用这个库。这是你要找的吗？

  #include< chrono> 
 #include< iostream> 
 
 int main（）
 {
 typedef std :: chrono :: high_resolution_clock时间; 
 typedef std :: chrono :: milliseconds ms; 
 typedef std :: chrono :: duration< float> fsec; 
 auto t0 = Time :: now（）; 
 auto t1 = Time :: now（）; 
 fsec fs = t1  -  t0; 
 ms d = std :: chrono :: duration_cast< ms>（fs）; 
 std :: cout<< fs.count（）< s\\\
; 
 std :: cout<< d.count（）<< ms\\\
; 
} 
  

其中打印出：

  6.5e-08s 
 0ms 
  

I'm trying to use chrono library for timers and durations.

I want to be able to have a Duration frameStart; ( from app start ) and a Duration frameDelta; ( time between frames )

I need to be able to get the frameDelta duration as milliseconds and float seconds.

How do you do this with the new c++11 <chrono> libraries? I've been working on it and googling ( information is sparse ). The code is heavily templated and requires special casts and things, I can't figure out how to use this library correctly.

解决方案

Is this what you're looking for?

#include <chrono>
#include <iostream>

int main()
{
    typedef std::chrono::high_resolution_clock Time;
    typedef std::chrono::milliseconds ms;
    typedef std::chrono::duration<float> fsec;
    auto t0 = Time::now();
    auto t1 = Time::now();
    fsec fs = t1 - t0;
    ms d = std::chrono::duration_cast<ms>(fs);
    std::cout << fs.count() << "s\n";
    std::cout << d.count() << "ms\n";
}

which for me prints out:

6.5e-08s
0ms

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