科学计算器。可以解读表达式，进行整数、浮点数的加减乘除运算。-Scientific calculator. Expression can be interpreted, for integer, floating-point addition and subtraction, multiplication and division calculations.

在以二叉树表示算术表达式的基础上，设计一个十进制的四则运算的计算器。[设计要求]实现整数浮点数的四则运算，并且还加上了^的运算，支持括号及开始的负数-In a binary arithmetic expression that is designed based on a four decimal arithmetic calculator. [Design requirements] to achieve a four-integer floating-point arithmetic, an