1. There is some redundant code in the two stack classes discussed in this section. Which code is it, and how could it be eliminated by the use of inheritance? 2. For the case study, we present a...

1. There is some redundant code in the two stack classes discussed in this section. Which code is it, and how could it be eliminated by the use of inheritance?

2. For the case study, we present a program that evaluates postfix expressions. The program allows the user to enter an arbitrary postfix expression and then displays the expression’s value or an error message if the expression is invalid. The stackbased algorithm for evaluating postfix expressions is at the heart of the program.