设计一个程序，演示用算符优先法对算术表达式求值的过程。利用算符优先关系，实现对算术四则混合运算表达式的求值。
（1）输入的形式：表达式，例如2*(3+4)
　　 包含的运算符只能有'+' 、'-' 、'*' 、'/' 、'('、 ')'；
（2）输出的形式：运算结果，例如2*(3+4)=14；
（3）程序所能达到的功能：对表达式求值并输出(A program is designed to demonstrate the process of evaluating arithmetic expressions with the operator precedence method. The value of the arithmetic four expression is realized by using the operator priority relation.

(1) the form of input: expression, such as 2* (3+4)

The operator can only contain a '+' and '-', '*', ',' ('and')';

(2) the form of output: the result of operation, such as 2* (3+4) =14;

(3) the function that the program can achieve: the evaluation and output of the expression)