stdafx.h is a file that is create by Visual C++ for you when you create a project.
Either you have moved you code file out of it's original project directory without moving stdafx.h, or you have deleted the stdafx.h that VC++ created without removing the #include.
Since stdafx.h is a part of you project source code if you are not using it then just remove the #include.
That is because failing to find an include file is such a critical error that generally the compiler stops imediately and doesn't compile any more of the file thus masking any errors in it.
Anyway stdafx.h will only have had what you put into it (in might have included "windows.h" ).
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