Introduction - If you have any usage issues, please Google them yourself
An arithmetic expression is an operand (operand), operator (operator) and boundary character (delimiter) thereof. Suppose is a positive integer operands, operators containing only addition, subtraction and other four operators, boundary character left and right parentheses and expressions start and end symbol # , such as:# (7+ 15)* (23-28/4)#. Introducing expressions start and end character is for convenience. Programming using the operator precedence Evaluate arithmetic expressions.
[basic requirements]
(1) Reading the keyboard into a legitimate arithmetic expressions, output the correct result.
(2) changes in the sequence and displays the input process stack.