stdafx.h : 标准系统包含文件的包含文件。 Microsoft C 和 C++ 编译器提供了用于预编译任何 C 或 C++ 代码（包括内联代码）的选项。利用此性能特性，可以编译稳定的代码体，将已编译状态的代码存储在文件中，以及在随后的编译中，将预编译的代码与仍在开发的代码结合起来。由于不需要重新编译稳定代码，因此后面每次编译的速度都要快一些。
VC中的StdAfx头文件 // stdafx.h : include file for standard system include files, // or project specific include files that are used frequently, but // are changed infrequently // #if !defined(AFX_STDAFX_H__58C73787_1231_40B3_A8BC_2F7670ABA3D7__INCLUDED_)
StdAfx.h下载 stdafx.h : include file for standard system include files, or project specific include files that are used frequently, but are changed infrequently
代码： // stdafx.h : include file for standard system include files, // or project specific include files that are used frequently, but // are changed infrequently // #if !defined(AFX_STDAFX_H__C4B5DA9B_21EA_47D6_9253_A4245E58FBF5__INCLUDED_) #define A
