This thesis introduces the analysis and design of the sketchpad software based on VC + + compiler environment and the language of C++.
The main ideas is using MFC to write out the code to respond the user’s mouse movements and clicks ,to realise Sketchpad features. The main process of program is: first, build new virtual base classes,program virtual functions and public members.second, build new derived class, write their own specific functions to achieve the Specific function. Third，conbain the user's operation and the specific function of derived classes, program the code of user's operation . Forth, program the code of saving function. Fifth, debugging the program, improve the code efficiency.
This design, basically realise sketchpad software’s functions of drawing lines, circles, and square ,and add save and open functions.
