Window系统下C/C++程序毫秒和微秒级程序运行时间的获取方法

一、使用clock()函数，获取毫秒级(ms)时间[1]

#include <time.h>//clock()头文件

clock_t start = clock();

   {statement section}//测试代码段

clock_t end = clock();

printf("the running time is :%fs\n", (double)(end -start)/(double)CLOCKS_PER_SEC); //秒

二、基于CPU级的方法，获取微秒级(us)时间[2,3]

#include <stdio.h>
#include <windows.h>//头文件

LARGE_INTEGER nFreq;

LARGE_INTEGER t1;

LARGE_INTEGER t2;

double dt;

 QueryPerformanceFrequency(&nFreq);
 QueryPerformanceCounter(&t1);

      {statementsection}//测试代码段
  QueryPerformanceCounter(&t2);
  dt = （t2.QuadPart - t1.QuadPart） / (double)nFreq.QuadPart;
  cout<<"Running time :"<<dt*1000<<"ms"<<endl;//dt结果乘以1000,将显示时间调整到ms级别显示，乘以1000000，将显示时间调整到us级别显示

备注：可以在代码段添加Sleep()函数测试，如下两个测试实例。

例1：500ms

time_t start = clock();
   Sleep(1000);//500ms
time_t end = clock();
printf("the running time is :%fms\n", (double)(end -start));

运行结果，如下：

the running time is :1001.000000ms

例2: 5ms测试 

 LARGE_INTEGER  nFreq,t1,t2;
double dt;
QueryPerformanceFrequency(&nFreq);
QueryPerformanceCounter(&t1);
Sleep(5);//5ms,其中1ms=1000us
QueryPerformanceCounter(&t2);
 dt = (t2.QuadPart - t1.QuadPart)/(double)nFreq.QuadPart;
cout<<"Running time : "<<dt*1000000<<"us"<<endl;

运行结果，如下：

Running time : 5162.22us
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作者：泡泡徐 
来源：CSDN 
原文：https://blog.csdn.net/xpplearnc/article/details/53894048 
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