Chapter 13, Problem 17E

Explanation of Solution

Program method

• The comparator that compares String objects of a particular format is

  // Compares Strings objects of a particular format

  public class CityComparator implements Comparator<String>

  {

      //Declare method compare

  public int compare(String s1, String s2)

  {

      //Declare scan1 and scan2

  Scanner scan1 = new Scanner(s1);

  Scanner scan2 = new Scanner(s2);

  //Declare code1 and code2

 int code1 = scan1.nextInt();

  int code2 = scan2.nextInt();

  //Define if condition

  if (code1 != code2)

 {

  return code1 - code2;

  }

  //Declare city1 and city2

  String city1 = scan1...