此算术表达式解析器能够在程序运行时根据输入的变量大小和算术表达式动态解析表达式，得到运算结果。支持多项算术运算符和数学函数如下：: + - * / ^ ( ) mod abs, atan, cos, exp, ln, round, sin, sqrt, sqr, trunc-this arithmetic expression parser procedures in the light of input variable size and arithmetic expressions Dynamic Analysis expression, to be Operational results. Support a number of arithmetic operations and mathematical functions are as follows : :-* / ^ () mod abs, atan, cos. exp, ln, round, sin, sqrt, sqr, trunc