记录程序运行时间 精确到ms

[zedzhao]

好像用clock()人家说是精确到s
GetTickCount() 我试了 不行的 不知道该包含哪个头文件 或者有什么别的方法记录时间
越精确越好 也不用特别精确 一个课程设计用的

[funnybunny]

调用2次API的GetSystemTime或者 GetLocalTime可以吧，详见MSDN~

[zedzhao]

给个例子行吗
主要就是 好像这些API用不了 提示
error C3861: “GetTickCount”: 找不到标识符

[agaric]

... 有没有包含windows.h？？

[zedzhao]

汗~~~~没有
我以为c++下的都不用.h的了..
#include <cwindows> 不行就不知道怎么办了...

可是 GetTickCount() 和 clock()的精度一样吗？

[SKYNORAIN]

多查查MSDN
GetTickCount

The GetTickCount function retrieves the number of milliseconds that have elapsed since the system was started. It is limited to the resolution of the system timer. To obtain the system timer resolution, use the GetSystemTimeAdjustment function.


DWORD GetTickCount(void);

Parameters
This function has no parameters.
Return Values
The return value is the number of milliseconds that have elapsed since the system was started.

Remarks
The elapsed time is stored as a DWORD value. Therefore, the time will wrap around to zero if the system is run continuously for 49.7 days.

If you need a higher resolution timer, use a multimedia timer or a high-resolution timer.

To obtain the time elapsed since the computer was started, retrieve the System Up Time counter in the performance data in the registry key HKEY_PERFORMANCE_DATA. The value returned is an 8-byte value. For more information, see Performance Monitoring.

Example Code
The following example demonstrates how to use a this function to wait for a time interval to pass. Due to the nature of unsigned arithmetic, this code works correctly if the return value wraps one time. If the difference between the two calls to GetTickCount is more than 49.7 days, the return value could wrap more than one time and this code will not work; use the system time instead. Note that TIMELIMIT is defined as the time interval of interest to the application, in milliseconds.

DWORD dwStart = GetTickCount();

// Stop if this has taken too long
if( GetTickCount() - dwStart >= TIMELIMIT )
Cancel();

Requirements
Client Requires Windows XP, Windows 2000 Professional, Windows NT Workstation, Windows Me, Windows 98, or Windows 95.
Server Requires Windows Server 2003, Windows 2000 Server, or Windows NT Server.
Header Declared in Winbase.h; include Windows.h.

Library Link to Kernel32.lib.

DLL Requires Kernel32.dll.

[zedzhao]

GetTickCount()在MSDN里我有找到,不过clock()没找到，
我测试了下 好像2个精度一样的