在实际software开发工作中，我们经常会测试某个module或者function的执行效率。或者是某个算法的时间复杂度(虽然时间复杂度一定程度上依赖于机器性能，但在同一台computer上，经过算法优化，可以测试其复杂度)；这时候就需要精确获取时间，才可以准确的运行时间，下面的函数实现了精确计时，计时精度可以达到微秒级；可用于测试某个模块的效率！
//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;
// 生成内容
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 清晰有书签PDF+源代码
将C语言梳理一下，分布在以下10个章节中：
Linux-C成长之路（一）：Linux下C编程概要
Linux-C成长之路（十）：其他高级议题