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iOS Object-Oriented Swift Inheritance Overriding Methods

David Petrin
David Petrin
3,384 Points
Posted by David Petrin
David Petrin
3,384 Points

Overriding Method Challenge Task Problem with Code

Not sure what I am doing wrong with this task here. Anyone have any suggestions?

Button.swift 
class Button {
  var width: Double
  var height: Double

  init(width:Double, height:Double){
    self.width = width
    self.height = height
  }

  func incrementBy(points: Double) -> (Double, Double) {
    return(width + points, height + points)
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0
  override func incrementBy(_ points: Double = 7.0) -> (Double, Double) {
        return super.incrementBy(points)
}

4 Answers

William Li
PLUS
William Li
Courses Plus Student 26,868 Points
William Li
William Li
Courses Plus Student 26,868 Points

Hi, David Petrin

Aside from the missing closing bracket pointed out by Michael Hulet , there's another fatal problem with your code.

You modified the return type of the original incrementBy method, which you shouldn't do; also, it's incorrect to add return type for method with no return value. The challenge is expecting the incrementBy method be intact, and only override its implementation (slightly) in the RoundButton class.

Our RoundButton class should have its own implementation of the incrementBy method. Override the incrementBy method in the RoundButton class and default the points parameter to 7.0.

class Button {
  var width: Double
  var height: Double

  init(width:Double, height:Double){
    self.width = width
    self.height = height
  }

  func incrementBy(points: Double){
    width += points
    height += points
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0
  override func incrementBy(_ points: Double = 7.0) {
        return super.incrementBy(points)
  }
}

This should do it.

Michael Hulet
Michael Hulet
47,912 Points
Michael Hulet
Michael Hulet
47,912 Points

Just glancing at it, I can see you're missing the closing bracket of the override function. Try this:

class Button {
  var width: Double
  var height: Double

  init(width:Double, height:Double){
    self.width = width
    self.height = height
  }

  func incrementBy(points: Double) -> (Double, Double) {
    return(width + points, height + points)
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0
  override func incrementBy(_ points: Double = 7.0) -> (Double, Double) {
        return super.incrementBy(points)
  //The following closing bracket didn't exist in your original code
  }
}
David Petrin
David Petrin
3,384 Points
David Petrin
David Petrin
3,384 Points

Thanks, I did correct that. However, it gives me an error stating "You didn't add the 'incrementBy' method to the class 'RoundBotton' or click preview for compile errors. There are no compile errors. Is the code correct, but just not in the form (e.g. the function was modified to return a tuple) the challenge wanted?

Kieran Tross
Kieran Tross
8,266 Points
Kieran Tross
Kieran Tross
8,266 Points

See my code below. It doesn't work 

class Button {
  var width: Double
  var height: Double

  init(width:Double, height:Double){
    self.width = width
    self.height = height
  }

  func incrementBy(points: Double){
    width += points
    height += points
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0

  override func incrementBy(_ points: Double = 7.0) -> (Double) {
        return super.incrementBy(points)

    }
}

anyone know the answer ?

Michael Hulet
Michael Hulet
47,912 Points
Michael Hulet
Michael Hulet
47,912 Points

  1. In the future, you should open your own question.

  2. You're modifying the return type of your incrementBy function in your RoundButton subclass. Every override function needs to have the same return type as the function it's overriding. Try this:

class Button {
  var width: Double
  var height: Double

  init(width:Double, height:Double){
    self.width = width
    self.height = height
  }

  func incrementBy(points: Double){
    width += points
    height += points
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0

  //Notice how this function declares no return type, and also never returns anything
  override func incrementBy(_ points: Double = 7.0){
        super.incrementBy(points)
    }
}