在實際software開發工作中,我們經常會測試某個module或者function的執行效率。或者是某個算法的時間復雜度(雖然時間復雜度一定程度上依賴於機器性能,但在同一台computer上,經過算法優化,可以測試其復雜度);這時候就需要精確獲取時間,才可以准確的運行時間,下面的函數實現了精確計時,計時精度可以達到微秒級;可用於測試某個模塊的效率!
//Purpose :this programme is designed for testing the performance of your code ,some function ect,
//it can show the time of spending on your running on it . it is beneficial to improve your performance
//of code
// author :Jackery_shh
// data: July 8th 2015
#include<Windows.h>
#include<iostream>
#include<tchar.h>
using namespace std;
#define IN
#ifdef _DEBUG
#define _Trace_Size 500
inline void FileTrace(IN LPCTSTR szFormat, ...)
{
if (szFormat == NULL)
return;
TCHAR t_trace[_Trace_Size] = { _T('\0') };
va_list vl = NULL;
// 生成內容
va_start(vl, szFormat);
_vsntprintf_s(t_trace, _Trace_Size, _TRUNCATE, szFormat, vl);
va_end(vl);
OutputDebugString(t_trace);
}
#else
inline void FileTrace(IN LPCTSTR szFormat, ...){}
#endif
LARGE_INTEGER begin_time ,freq;
int main()
{
LARGE_INTEGER begin_time ,freq;
QueryPerformanceFrequency (&freq);
QueryPerformanceCounter (&begin_time);
//begin time
for (long test0=0;test0<5000000;test0++)
{
test0=test0+1;
}
LARGE_INTEGER end_time0;
QueryPerformanceCounter (&end_time0);
//after runnin the 'for' loop statement,the time is Time0
double Time0 = ((double) (end_time0.QuadPart - begin_time.QuadPart)*1000.0) / (double) (freq.QuadPart);
int test1=10000;
while (test1)
{
test1--;
}
LARGE_INTEGER end_time1;
QueryPerformanceCounter (&end_time1);
double Time1 = ((double) (end_time1.QuadPart - begin_time.QuadPart)*1000.0) / (double) (freq.QuadPart);
FileTrace(_T("*********************************************************************************\n"));
FileTrace(_T("Test result is as follow :\ntime: %I64x, %.3fms, %.3fms\n"), (ULONGLONG)0, Time0, Time1);
FileTrace(_T("*********************************************************************************\n"));
system("pause");
return 0;
}
C++ Primer Plus 第6版 中文版 清晰有書簽PDF+源代碼 http://www.linuxidc.com/Linux/2014-05/101227.htm
讀C++ Primer 之構造函數陷阱 http://www.linuxidc.com/Linux/2011-08/40176.htm
讀C++ Primer 之智能指針 http://www.linuxidc.com/Linux/2011-08/40177.htm
讀C++ Primer 之句柄類 http://www.linuxidc.com/Linux/2011-08/40175.htm
將C語言梳理一下,分布在以下10個章節中: