Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community!

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Object-Oriented Swift Value vs Reference Types Final Challenge

What's wrong?

Don't get it!

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()!