小型计算器代码.设计一个小型计算器可进行加、减、乘、除、乘方、开方、括号运算。该计算器不是根据输入运算符的先后而从头算到尾而没有进行运算符的优先级的判定，而是先判断运算符的优先级的高低然后依次进行计算的。上述的几种运算，可以在一位或多位的浮点数间进行运行并且可以准确的计算出结果。 -Small calculator code. Design a mini-calculator can be add, subtract, multiply, divide, involution, administration, operation parentheses. The calculator is not based on the input operator has to end and the ab initio no operator precedence to determine, but the first operator to determine the level of priority and then in turn be calculated. Several of these calculations can be one or more of the floating-point between the running and can accurately calculate the results.