a simple dos calculator in c

The following C project contains the C source code and C examples used for ^a simple dos calculator^. This is Simple DOS Calculator. It uses Graphics to display buttons and textbox. Understand the code and put some more function of your own. It really small and easy to understand. Please give me comments.

The source code and files included in this project are listed in the project files section, please make sure whether the listed source code meet your needs there.

Project Files: 

File NameSize
Calci.cpp 2106
Mouse.h 552
Winoop.h 3660