A C++ program to implement the algorithm for evaluating postfix expressions that involve integers with more than one digit and the integer operations +, -, *, /, %.
Displays each token as it is encountered and displays the action of each stack operation to trace the action of postfix evaluation. User enters a string representing the postfix expression, looping until a semicolon is input at the end of an expression. The unary operator _ is accepted to represent negative numbers. This program uses the stack class: https://cplusplus.com/reference/stack/stack/