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

Chase Maddox
PRO
Chase Maddox
Pro Student 5,461 Points

Apostrophe in Given Setup Causing Error or Bad Code?

Hi,

In the given setup for this Code Challenge there is an apostrophe in the word "I'm" of the given move() function that causes the rest of the code to be commented out. I deleted that apostrophe, but I'm not sure if that's what's causing my code to not be accepted as correct or how to keep it in and not have everything be commented out.

When I try my code in a separate Xcode playground it seems to work fine, and I'm able to create instances of Robot and use the override move() function to then check my location has moved.

Thanks, Chase

robots.swift
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! Im a machine!")
  }
}

// Enter your code below

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

    override func move(_ direction: String) {
        switch direction {
        case "Up": location.y += 1
        case "Down": location.y -= 1
        case "Right": location.x += 1
        case "Left" : location.x -= 1
        default: break
        }
    }
}

1 Answer

Chris Stromberg
PRO
Chris Stromberg
Pro Student 13,389 Points

Remove the following code. The challenge did not ask for you to provide a designated initializer for the Robot class.

init(x: Int, y: Int) {
        super.init()
    }

I don't think your code will work as you intend it to. The following will take in parameters you provide, however it will set the values of both x and y to zero. This is because you are calling super.init() which is calling the initializer in the base class.

init(x: Int, y: Int) {
        super.init()
    }

If you wanted to provide values for x and y, you would need to do something like this. I named the internal parameter names robotX and robotY for clarity.

 init(robotX : Int, robotY : Int) {
        super.init()
        //point : Point(x: robotX, y: robotY)
        self.location = Point(x: robotX, y: robotY)

    }
Chase Maddox
Chase Maddox
Pro Student 5,461 Points

Ahhh ok, thanks so much! I think I got so used to calling super.init() that I didn't even realize it didn't ask for it.