类似windows附件中自带的计算器

l 实现简单的四则运算功能和高级的科学计算功

能

l 界面设计要求简洁大方：

¡ 菜单栏

¡ 实现用户显示输入输出的编辑框

¡ 功能按钮，要求具有对鼠标敏感的功能（即鼠标

处于不同的位置和状态时，按钮控件会显示不同

的颜色，并且所有按钮控件的客户区域为椭圆或

圆形）-Similar to the windows in the annex built-in calculator l to achieve a simple four computing capabilities and advanced scientific computing l interface, simple and generous design requirements: ¡　Menu bar ¡　Realization of the user input and output of edit box ¡　Function button, and require a right mouse-sensitive functions (ie the mouse in a different location and state, the button control will display different colors, and all the button controls the client region to an oval or round)