lab5

lab/lab5/Question4/Start.java

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+/**
+ * Answer to question.
+ *
+ * # Question 4
+ *
+ * Q: Now that the Student class uses an animal as pet, can you still use a cat
+ * object as the pet of a student? Why or why not?
+ *
+ * A: Yes, you can. The Student class has a method getPet() that returns the pet
+ * which is Animal type.
+ *
+ * Q: Can you now use a dog object as the pet of a student? Why or why not?
+ *
+ * A: Yes, you can. But only attributes and methods definded in the Animal class
+ * can be accessed. When you do so, the Dog object will be converted to an
+ * Animal object. Assign a child object to a parent object is called upcasting
+ * in Java. Upcasting is implicit.
+ *
+ */
+public class Start {
+	public static void main(String[] args) {
+		Cat.testCat();
+		Dog.testDog();
+		Student.testStudent();
+		Animal.testAnimal();
+	}
+}