E10.10 Modify the Coin class from Chapter 8 to have it implement the Comparable interface.

Coin class:

/** A coin with a monetary value. */ public class Coin implements Comparable { private double value; private String name;

/** Constructs a coin. @param aValue the monetary value of the coin @param aName the name of the coin */ public Coin(double aValue, String aName) { value = aValue; name = aName; }

/** Gets the coin value. @return the value */ public double getValue() { return value; }

/** Gets the coin name. @return the name */ public String getName() { return name; }

}

Other classes in this exercise:

1)

/** A cash register totals up sales and computes change due. */ public class CashRegister { private double purchase; private double payment;

/** Constructs a cash register with no money in it. */ public CashRegister() { purchase = 0; payment = 0; }

/** Records the purchase price of an item. @param amount the price of the purchased item */ public void recordPurchase(double amount) { purchase = purchase + amount; } /** Enters the payment received from the customer. @param coinCount the number of coins received @param coinType the type of coin that was received */ public void receivePayment(int coinCount, Coin coinType) { payment = payment + coinCount * coinType.getValue(); } /** Computes the change due and resets the machine for the next customer. @return the change due to the customer */ public double giveChange() { double change = payment - purchase; purchase = 0; payment = 0; return change; } }

2)

/** A class to test the CashRegister class. */ public class CashRegisterTester { public static void main(String[] args) { final Coin DOLLAR = new Coin(1.0, "Dollar"); final Coin QUARTER = new Coin(0.25, "Quarter");

CashRegister register = new CashRegister();

register.recordPurchase(1.95); register.recordPurchase(1.40); register.receivePayment(3, DOLLAR); register.receivePayment(2, QUARTER);

double change = register.giveChange();

System.out.println(change); System.out.println("Expected: 0.15"); } }