Introduction - If you have any usage issues, please Google them yourself
Demonstration by operator precedence for arithmetic expression evaluation process. (1) from the keyboard input any grammatically correct (infix) expression, display and save the expression. (2) use of the stack structure, the (infix) expression into a postfix expression and display the stack status change process and the postfix expression. (3) the use of stack structure, the postfix expression is evaluated, and display the stack status change process and the final result.