C_C++ 各種計時函數

 對Windows平台下常用的計時函數進行總結，包括精度為秒、毫秒、微秒三種精度的5 種方法。分為在標准C/C++下的二種time()及clock()，標准C/C++所以使用的time()及clock()不僅可以用在Windows 系統，也可以用於Linux系統。

在Windows系統下三種，使用Windows提供的API接口timeGetTime()、 GetTickCount()及QueryPerformanceCounter()來完成。

[cpp]
#include <windows.h>    
#include <time.h> //time_t time()  clock_t clock()    
#include <Mmsystem.h>             //timeGetTime()    
#pragma comment(lib, "Winmm.lib")   //timeGetTime()    
 
int main(int argc, char* argv[]) 
{ 
    //用time()來計時  秒    
    time_t timeBegin, timeEnd;   
    timeBegin = time(NULL);   
    Sleep(800);   
    timeEnd = time(NULL);   
    printf("time %d\n", timeEnd - timeBegin);   
     
     
    //用clock()來計時  毫秒    
    clock_t  clockBegin, clockEnd;   
    clockBegin = clock();   
    Sleep(800);   
    clockEnd = clock();   
    printf("clock %d\n", clockEnd - clockBegin);   
     
     
    //用timeGetTime()來計時  毫秒    
    DWORD  dwBegin, dwEnd;   
    dwBegin = timeGetTime();   
    Sleep(800);   
    dwEnd = timeGetTime();   
    printf("timeGetTime %d\n", dwEnd - dwBegin);   
     
     
    //用GetTickCount()來計時  毫秒    
    DWORD  dwGTCBegin, dwGTCEnd;   
    dwGTCBegin = GetTickCount();   
    Sleep(800);   
    dwGTCEnd = GetTickCount();   
    printf("GetTickCount %d\n", dwGTCEnd - dwGTCBegin);   
     
     
    //用QueryPerformanceCounter()來計時  微秒    
    LARGE_INTEGER  large_interger;   
    double dff;   
    __int64  c1, c2;   
    //獲取是否支持精確定時器。 定時器的頻率  
    if( QueryPerformanceFrequency(&large_interger) ) 
    { 
        dff = large_interger.QuadPart;  
        //獲取定時器的值  
        QueryPerformanceCounter(&large_interger);   
        c1 = large_interger.QuadPart;   
        Sleep(800);   
        //獲取定時器的值  
        QueryPerformanceCounter(&large_interger);   
        c2 = large_interger.QuadPart;   
        printf("本機高精度計時器頻率%lf\n", dff);   
        printf("第一次計時器值%I64d 第二次計時器值%I64d 計時器差%I64d\n", c1, c2, c2 - c1);   
        printf("計時%lf毫秒\n", (c2 - c1) * 1000 / dff);   
        printf("\n");    
    } 
 
    return 0;   
} 

#include <windows.h> 
#include <time.h> //time_t time()  clock_t clock() 
#include <Mmsystem.h>             //timeGetTime() 
#pragma comment(lib, "Winmm.lib")   //timeGetTime() 

int main(int argc, char* argv[])
{
    //用time()來計時  秒 
    time_t timeBegin, timeEnd; 
    timeBegin = time(NULL); 
    Sleep(800); 
    timeEnd = time(NULL); 
    printf("time %d\n", timeEnd - timeBegin); 
   
   
    //用clock()來計時  毫秒 
    clock_t  clockBegin, clockEnd; 
    clockBegin = clock(); 
    Sleep(800); 
    clockEnd = clock(); 
    printf("clock %d\n", clockEnd - clockBegin); 
   
   
    //用timeGetTime()來計時  毫秒 
    DWORD  dwBegin, dwEnd; 
    dwBegin = timeGetTime(); 
    Sleep(800); 
    dwEnd = timeGetTime(); 
    printf("timeGetTime %d\n", dwEnd - dwBegin); 
   
   
    //用GetTickCount()來計時  毫秒 
    DWORD  dwGTCBegin, dwGTCEnd; 
    dwGTCBegin = GetTickCount(); 
    Sleep(800); 
    dwGTCEnd = GetTickCount(); 
    printf("GetTickCount %d\n", dwGTCEnd - dwGTCBegin); 
   
   
    //用QueryPerformanceCounter()來計時  微秒 
    LARGE_INTEGER  large_interger; 
    double dff; 
    __int64  c1, c2; 
    //獲取是否支持精確定時器。 定時器的頻率
    if( QueryPerformanceFrequency(&large_interger) )
    {
        dff = large_interger.QuadPart;
        //獲取定時器的值
        QueryPerformanceCounter(&large_interger); 
        c1 = large_interger.QuadPart; 
        Sleep(800); 
        //獲取定時器的值
        QueryPerformanceCounter(&large_interger); 
        c2 = large_interger.QuadPart; 
        printf("本機高精度計時器頻率%lf\n", dff); 
        printf("第一次計時器值%I64d 第二次計時器值%I64d 計時器差%I64d\n", c1, c2, c2 - c1); 
        printf("計時%lf毫秒\n", (c2 - c1) * 1000 / dff); 
        printf("\n");  
    }

    return 0; 
}