如何显示:unexpected end of file while looking for precompiled header directive

怎么显示:unexpected end of file while looking for precompiled header directive
在MFC里,我添加了两个文件如下:
/////////a.cpp
int   add   (int   x,int   y)
{
return   x   +   y;
}
/////////a.h
int   add   (int   x,int   y);
/////////
然后把a.h添加到stdafx.h里,怎么显示a.cpp里有错误:unexpected   end   of   file   while   looking   for   precompiled   header   directive。求助。

------解决方案--------------------
在a.h和a.cpp都加入
#include "stdafx.h "