Problem
Write a program that reads postfix expressions and prints their values. Each input expression should be entered on its own line, and the program should terminate when the user enters a blank line. Please do error checking for any error.
Assume only binary operators, and that the expressions contain no variables. Note that you will need to use parentheses to indicate the order of application of the operators in the expression.
Here are sample input-output pairs:
inputs outputs
78 78
78 6 + 84
78 6 + 9 2 - / 12
78 + error
2 + 3 error
2 3 + 4 error