Classy Puzzlers - Java Puzzlers: Traps, Pitfalls, and Corner Cases - page 130

< Day Day Up >
Puzzle 47: Well, Dog My Cats!
This program uses a Counter class to keep track of how many times each kind of house pet makes a
noise. What does the program print?
class Counter {
private static int count;
public static void increment() { count++; }
public static int getCount() { return count; }
}
class Dog extends Counter {
public Dog() { }
public void woof() { increment(); }
}
class Cat extends Counter {
public Cat() { }
public void meow() { increment(); }
}
public class Ruckus {
public static void main(String[] args) {
Dog dogs[] = { new Dog(), new Dog() };
for (int i = 0; i < dogs.length; i++)
dogs[i].woof();