Have the Address class implement the Comparable interface. First compare the street name, then the house number. For example, 123 Main Street comes after 57 Main Street but before 1 State Street.

public class Address implements Comparable { private String street; private int houseNumber;

/** Constructs an address. @param aStreet the street name @param aHouseNumber the house number */ public Address(String aStreet, int aHouseNumber) { street = aStreet; houseNumber = aHouseNumber; }

public String toString() { return houseNumber + " " + street; }

/* Your code goes here */

}

import java.util.Arrays; public class Tester { public static void main(String[] args) { Address[] addresses = { new Address("Main Street", 123), new Address("Main Street", 57), new Address("Hollywood Ave", 11235) }; System.out.println(addresses[0].compareTo(addresses[0])); System.out.println("Expected: 0"); System.out.println(addresses[0].com reTo(addresses[1]) > 0) System.out.println("Expected: true"); System.out.println(addresses [1].compareTo(addresses [2]) 0); System.out.println("Expected: true"); System.out.println(addresses [2].compareTo(addresses[1]) > 0); System.out.println("Expected: false"); Arrays.sort (addresses); System.out.println(Arrays.toString(addresses)); System.out.println( "Expected: [11235 Hollywood Ave, 57 Main Street, 123 Main Street]"); } }