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iOS Object-Oriented Swift Value vs Reference Types Final Challenge

What's wrong?

Don't get it!

Vehicle.swift
class Vehicle {
    let wheels: Int
    let doors: Int

    // Designated initializer
    init(wheels:Int, doors:Int){
        self.wheels = wheels
        self.doors = doors
    }
}

class Car: Vehicle {
    // A car must default to 4 wheels and 4 doors
    wheels = 4
    doors = 4
      // call super.init
      super.init(wheels: wheels){
    }
}

1 Answer

There are a few things wrong with your Car class:

  • You deleted the start of the init() block
  • Trying to assign values to the wheels and doors properties won't work outside a method
  • Your call to super.init() is formatted incorrectly

Your Vehicle class looks good though!

Remember that super is like an instance of the Vehicle class, so you call the init() method just like calling any other class method. Get rid of the extra lines where you're assigning values to wheels and doors. In order to make a Car default to 4 wheels and 4 doors, you can pass those numbers into super.init()!