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iOS Build a Simple iPhone App with Swift Getting Started with iOS Development Swift Recap Part 2

What am I missing? The code passes in Xcode but not Treehouse.

This is what I receive as an error from Treehouse.

swift_lint.swift:32:19: error: argument names for method 'move(direction:)' do not match those of overridden method 'move' override func move(direction: String){ ^ _

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 {
    override func move(direction: String){
        switch direction{
        case "Up" : location.y += 1
        case "Down" : location.y -= 1
        case "Left" : location.x -= 1
        case "Right" : location.x += 1
        default : break
Matt Skelton
Matt Skelton
4,548 Points

You'll kick yourself once you see it, though it's such an easy one to get tripped up by!

You've spotted the line that's throwing the error, the problem is that your override function signature doesn't quite match the one outlined in the parent class. The compiler is very particular, and your parent class has an external name of '_', whereas the overridden function doesn't have an external name.

Make sure your external and internal parameter names match up and you should be good to go!

2 Answers

I think it should be fine if you add an underscore to your function like the superclass function

override func move(_ direction: String){

Thanks to both of you! Always good to have another set of eyes. You both rock!