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Ali Bouland
3,479 PointsCode won't work..
Any idea why? Probably something very simple..
class Vehicle {
var numberOfDoors: Int
var numberOfWheels: Int
init(withDoors doors: Int, andWheels wheels: Int) {
self.numberOfDoors = doors
self.numberOfWheels = wheels
}
}
class Car: Vehicle {
var numberOfSeats = 4
override init(withDoors : Int, andWheels: Int){
super.init(withDoors: withDoors, andWheels: andWheels)
}
}
var someCar = Car(withDoors:2, andWheels: 4)
// Enter your code below
2 Answers
Nathan Tallack
22,159 PointsAli, you are overthinking. When you are subclsasing, you can avoid declaring an initializer if your properties in your subclass are optional or have default values. In this case your Car.numberOfSeats has a default value. So if you do not delcare an initializer you can make use of the parent class initializer without any extra effort. :)
Of course this means you can't initialize a different numberOfSeats when you are making your Car, but you can go ahead and change that poperty later after you have your object created. :)
So your code would look like this.
class Vehicle {
var numberOfDoors: Int
var numberOfWheels: Int
init(withDoors doors: Int, andWheels wheels: Int) {
self.numberOfDoors = doors
self.numberOfWheels = wheels
}
}
class Car: Vehicle {
var numberOfSeats = 4
}
let someCar = Car(withDoors:2, andWheels: 4)
Reed Carson
8,306 Pointsfor your override init you have deviated from the challenge parameters. you need
override init(withDoors doors: Int, andWheels wheels: Int) {
super.init(withDoors: doors, andWheels: wheels)
}
you have to be very careful about being specific for the code challenges, which is true to coding in the real world as well
Nathan Tallack
22,159 PointsThey are trying to teach you good coding practice too. By using the external names that are more descriptive it helps the developer that is using your class in the future by offering "natural language" for the parameters. You'll notice that being used alot by Apple's own frameworks.
Of course, you wont want to be using the big long parameter names within your method, so the internal name will be nice and short (but still descriptive) allowing you to code a little cleaner.
Ali Bouland
3,479 PointsAli Bouland
3,479 PointsWhat I don't understand is this part:
init(withDoors doors: Int, andWheels wheels: Int)why don't we just write: init(doors: Int, wheels: Int). What's the benefit of "withDoors doors" compared to just "doors"?