class Dog extends Animal implements Comparable<Dog> {

    
  public int compareTo( Dog other ) {
    if (this.getAge() < other.getAge()) {
      return -1;  // Any negative number is good enough to satisfy the interface.
      }
    else if (this.getAge() == other.getAge()) {
      return 0;
      }
    else if (this.getAge() > other.getAge()) {
      return +1;  // Any positive number will suffice.
      }
    else {
      System.err.println( "Shouldn't reach this far." );
      return 0;  // Better than returning a bad answer: Throw an exception.
      }
      }
    
    
  /** A Constructor when given a name and a sound.
   */
  public Dog( String nom, String sound ) {
    super( nom, sound );
    }

  /** The sound *most* dogs make. */
  private static final String DEFAULT_SOUND = "arf";

  /** A constructor given a name only.
   */
  public Dog( String nom ) {
    this( nom, DEFAULT_SOUND );  // Call the two-argument constructor.
    }

  public String wagTail() {
    return name + ": " + "[OhBoyOhBoyOhBoy!]";
    }

  public String speak() { return this.wagTail(); }

  }