Open the Ship.h file.

We need to add custom getters and setters to the hitpoints property, so let's make this property nonatomic and add an instance variable called _hitpoints.

Declare the methods abortShooting and hit.

Switch to the Ship.m file.

The custom hitpoints getter just returns the instance variable _hitpoints.

The custom setter for hitpoints contains the following code:

-(void) setHitpoints:(int)hitpoints
{
    _hitpoints = hitpoints;
    if (_hitpoints <= 0) {
        self.visible = NO;
    }
}

The abortShooting method consists of the following lines:

-(void) abortShooting
{
    _isShooting = NO;
    
    [Sparrow.juggler removeObjectsWithTarget:self.cannonBallLeft];
    [Sparrow.juggler removeObjectsWithTarget:self.cannonBallRight];
    
    self.cannonBallLeft.visible = NO;
    self.cannonBallRight.visible = NO;
}

The hit method has the following content...