1、实现界面设计：一个软件框；0-9数字按钮及小数点；加、减、乘、除、正负号、百分号、开方sqrt、倒数、等于运算符号；清除一位按键，及复位按钮；
2、实现计算功能：实数范围内最基本的加、减、乘、除四则运算及正负转换、开方、取倒数、百分数转换；
3、实现一位清除及复位功能：通过点击Back按钮实现数据的一位清除；通过点击C按钮实现数据的复位（清零）功能。(1, the realization of the interface design: a software frame; 0-9 digital button and the decimal point; addition subtraction multiplication and division, sign, sign, sqrt, is equal to the reciprocal, square root operation symbols; a clear button, and a reset button;
2, the computing range of the real: the most basic addition, subtraction, multiplication and four operations and the positive and negative conversion, reciprocal, square root, percentage of conversion;
3, achieve a function of clearance and reset: click the Back button to achieve data clearance; click the C button to achieve data reset (reset) function.)