On page 426 of Big Java: Late Objects, complete the review exercises:

R8.1 What is encapsulation? Why is it useful?

R8.2 What values are returned by the calls reg1.getCount(), reg1.getTotal(), reg2.getCount(), and reg2.getTotal() after these statements?

CashRegister reg1 = new CashRegister(); reg1.addItem(3.25); reg1.addItem(1.95); CashRegister reg2 = new CashRegister(); reg2.addItem(3.25); reg2.clear();

R8.3 Consider the Menu class in Worked Example 8.1. What is displayed when the following calls are executed?

Menu simpleMenu = new Menu(); simpleMenu.addOption("Ok"); simpleMenu.addOption("Cancel"); int response = simpleMenu.getInput();

R8.4 What is the public interface of a class? How does it differ from the implementation of a class?