Strategy 5

An abstract class is like an interface except you can include code. Since it is a class, the rule of “you can only extend one class” applies, so it actually has a different job than an interface even though it looks similar.

1. Make an abstract class Q with:

   • Constructor that takes in the String favorite food.
   • Abstract methods void eat(), void washHands() and void brushTeeth().
   • Concrete method: void lunch() which does wash hands and eat.
   • Concrete method: void dinner() which does wash hands, eat, and brush teeth.
   • A String ff() method to get the favorite food.

2. Create a class R extending Q.

   • Constructor takes in the favorite food.
   • Wash hands prints out “hands are clean”
   • Brush teeth prints out “happy teeth”
   • Eat prints out “Crunch crunch crunch”

3. Create a class RR extending R.

   • Constructor takes in a favorite food.
   • Eat is changed so that it prints out “Cheerios” the first time it is called, “Sandwich” the second time, and the favorite food every time after that.

4. Create RRR extending RR.

   • Favorite food is always “pasta”.
   • Instead of washing hands it prints “my hands are clean enough”.

5. Tester/puzzle code:

public static void testQ(Q x) {
    x.lunch();
    x.dinner();
}
public static void tester() {
    RR x = new RRR();
    R y = new RR("Frijoles");
    R z = new R("Banana cream pie");
    
    testQ(x);
    testQ(y);
    testQ(z);   
    
}