选中他们按右键可以察看他们在MFC中的定义
例如:
(...\Microsoft Visual Studio\VC98\Include\windef.h)
typedef int INT;
typedef unsigned int UINT;
typedef unsigned long DWORD;
typedef unsigned short WORD;
UINT A 16-bit unsigned integer on Windows versions 3.0 and 3.1; a 32-bit unsigned integer on Win32.
WORD A 16-bit unsigned integer.
DWORD A 32-bit unsigned integer or the address of a segment and its associated offset.
等等
学习vc,要多看msdn