//Windows系统下可以用 time()，clock()，timeGetTime()，GetTickCount()，QueryPerformanceCounter()来对一段程序代码进行计时 #include <stdio.h> #include <windows.h> #include <time.h>                   //time_t time()  clock_t clock()    #include <Mmsystem.h>               //timeGetTime()    #pragma comment(lib, "Winmm.lib")   //timeGetTime()    //使用方法：将Sleep()函数换成需要测试运行时间的函数即可。 int main() {   //用time()来计时，以秒为单位     time_t timeBegin, timeEnd;     timeBegin = time(NULL);     Sleep(1000);     timeEnd = time(NULL);     printf("%d\n", timeEnd - timeBegin);     //用clock()来计时，以毫秒为单位     clock_t  clockBegin, clockEnd;     clockBegin = clock();     Sleep(800);     clockEnd = clock();     printf("%d\n", clockEnd - clockBegin);     //用timeGetTime()来计时，以毫秒为单位     DWORD  dwBegin, dwEnd;     dwBegin = timeGetTime();     Sleep(800);     dwEnd = timeGetTime();     printf("%d\n", dwEnd - dwBegin);     //用GetTickCount()来计时，以毫秒为单位     DWORD  dwGTCBegin, dwGTCEnd;     dwGTCBegin = GetTickCount();     Sleep(800);     dwGTCEnd = GetTickCount();     printf("%d\n", dwGTCEnd - dwGTCBegin);     //用QueryPerformanceCounter()来计时，以微秒为单位     LARGE_INTEGER  large_interger;     double dff;     __int64  c1, c2;     QueryPerformanceFrequency(&large_interger);     dff = large_interger.QuadPart;     QueryPerformanceCounter(&large_interger);     c1 = large_interger.QuadPart;     Sleep(800);     QueryPerformanceCounter(&large_interger);     c2 = large_interger.QuadPart;     printf("本机高精度计时器频率%lf\n", dff);     printf("第一次计时器值%I64d\n第二次计时器值%I64d\n计时器差%I64d\n", c1, c2, c2 - c1);     printf("计时%lf毫秒\n\n", (c2 - c1) * 1000 / dff);     return 0; }