I can't understand why we don't need to override the initializing method

Anthony,

The reason you do not need to override init in this challenge is because it does not ask for the Robot class to have an initial location that differs from what the Machine class, it's parent class, is initialized with. The init method is passed on and accessible from Robot, because it is a superclass of Machine. The location variable gets initialized to x:0, y:0, when you instantiate a Robot class.

In this Challenge, if you just create the Robot class to be a superclass of Machine and not define anything:

class Point {
    var x: Int
    var y: Int

    init(x: Int, y: Int){
        self.x = x
        self.y = y
    }
}


class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! I'm a machine!")
    }
}

// Enter your code below

class Robot: Machine {

}

It is equivalent to saying:

class Point {
    var x: Int
    var y: Int

    init(x: Int, y: Int){
        self.x = x
        self.y = y
    }
}


class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! I'm a machine!")
    }
}

// Enter your code below

class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! I'm a machine!")
    }
}

Basically, you have the location variable, the init method and the move method. If you want to set self.location to something different then you would want to override init. If you wanted something else to happen when the move method is called, you override the move method.

If the challenge asked for Robot to start from a different location, then it would be necessary to override init. It would also be necessary to override init if the Robot class had defined it's own variables and it needed to initialized them.

Let me know if that makes sense.

Regards,

Florin

Simple answer

Machine is not a subclass of Point, therefore there is nothing to override in the init method

However if you did want to perform some overriding, it would look like this:

class Point { 
     var x: Int 
     var y: Int 

     init(x: Int, y:Int) { 
         self.x = x 
         self.y = y 
     } 
 } 


class Machine: Point { 
     override init(x:Int, y:Int){ 
         super.init(x: x, y:y) 
     } 
}