本代码是基于android开发的一个简易计算器，可进行加、减、乘、除、平方和开方等基本运算-The code is based on the the android developed a simple calculator can add, subtract, multiply, divide, square and square root basic operations

简单计算器,能实现加减乘除,平方开方,但有几个bug还没来得及修复-calculator,easy,a little bug