1、完善计算器程序，改为可对实数操作。

2、完善程序，改为多个操作数基本四则运算，遇到z为止。

3、增加函数，完成四则混合运算，增加相应的主菜单选项

4、添加语句，使四则运算具有测试功能。

5、可扩充其功能。

所给的计算器源程序中已有基本的加、减、乘、除和开方运算，我所要做的就是添加一个可以进行四则混合运算功能的类。

-A perfect calculator program, to be on the real operation.

       　2, improve the program, to more operands four basic arithmetic, z encountered so far.

       　3, increasing function, completed four mixed computing, the corresponding increase in the main menu options

       　4, the statement added that four operators with test function.

       　5, to expand its capabilities.

       　Given source program already have a basic calculator to add, subtract, multiply, divide and square root arithmetic class, I have to do is add a can carry four mixed computing functions.