abstract-classes

Clone / download repo and complete the following exercises. When you are done, push your changes back to GitHub.

1. display()
   Display the DeathStar and StarDestroyer.

2. Concrete Methods
   A concrete method is any non-abstract method in a class. How many concrete methods are in the abstract class Ship? Put a comment at the top of the class with this number.

3. move()
   Fill out the concrete method in Ship - move(). This method should increment x. If x is greater than the width of the screen, reset x to 0.

4. Override move()
   Override the move() method in the DeathStar class so that the DeathStar's y value moves in a wave:

y = (int) (30 * cos(x/10.0)) + 100);

Call the parent's move() method inside of the overridden method in order to continually increment x.

Call move() for both ships.

5. abstract fire()
   Add an abstract fire() method in Ship.

The implementation for fire() in DeathStar:

stroke(255, 0, 0);  
line(getX()- 10, getY() - 10, 0, getY());

The implementation for fire() in StarDestroyer:

stroke(255, 0, 0);
line(getX() * 2, getY() +10, getX() * 2 + 10, getY() +10);

Call fire() for both ships.

6. reflection
   Answer the questions at the top of the main class (AbstractShips) explaining why it might make sense to make the Ship class abstract, and how abstract classes might help code development. Also explain why it makes more sense for display() to be abstract but move() is concrete (but still overridden).