stdafx.h
is a file, generated by Microsoft Visual Studio IDE wizards, that describes both standard system and project specific include files that are used frequently but hardly ever change. Compatible compilers (for example, Visual C++ 6.0 and newer) will pre-compile this file to reduce overall compile times.Visual C++ will not compile anything before the
#include "stdafx.h"
in the source file, unless the compile option/Yu'stdafx.h'
is unchecked (by default); it assumes all code in the source up to and including that line is already compiled.