Exercise - Override Methods and Properties

note:

The exercises below are based on a game where a spaceship avoids obstacles in space. The ship is positioned at the bottom of a coordinate system and can only move left and right while obstacles "fall" from top to bottom. Throughout the exercises, you'll create classes to represent different types of spaceships that can be used in the game. The base class Spaceship and one subclass Fighter have been provided for you below.

class Spaceship {

var name: String = ""

var health = 100

var position = 0

func moveLeft() {

position -= 1

}

func moveRight() {

position += 1

}

func wasHit() {

health -= 5

}

}

class Fighter: Spaceship {

var weapon = ""

var remainingFirePower = 5

func fire() {

if remainingFirePower > 0 {

remainingFirePower -= 1

} else {

print("You have no more fire power.")

}

}

}

Define a new class ShieldedShip that inherits from Fighter. Add a variable property shieldStrength that defaults to 25. Create a new instance of ShieldedShip called defender. Set name to "Defender" and weapon to "Cannon." Call moveRight() and print position, then call fire() and print remainingFirePower.

Go back to your declaration of ShieldedShip and override wasHit(). In the body of the method, check to see if shieldStrength is greater than 0. If it is, decrement shieldStrength by 5. Otherwise, decrement health by 5. Call wasHit() on defender and print shieldStrength and health.

When shieldStrength is 0, all wasHit() does is decrement health by 5. That's exactly what the implementation of wasHit() on Spaceship does! Instead of rewriting that, you can call through to the superclass implementation of wasHit(). Go back to your implementation of wasHit() on ShieldedShip and remove the code where you decrement health by 5 and replace it with a call to the superclass' implementation of the method. Call wasHit() on defender, then print shieldStrength and health.

Note: prefered language"SWIFT"