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iOS Object-Oriented Swift Inheritance Overriding Methods

Why isn't this working?

This works in a playground.

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){
    width += points
    height += points
  }
}

class RoundButton: Button {
  var cornerRadius: Double = 5.0

  override func incrementBy(points: Double = 7.0){
    width += points
    height += points
  }
}

1 Answer

Michael Reining
Michael Reining
10,101 Points

Hi Christopher,

You need to set the points parameter equal to seven inside the method. Otherwise if you call the method and insert a new value such as 10, it will accept the new value.

You can easily test this in the playground.

Here is the code that worked for me.

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(var points: Double){
        points = 7 // set points to 7
        width += points
        height += points
    }
}

// For testing in playground
let roundButton = RoundButton(width: 5, height: 5)
roundButton.incrementBy(10) // the points value always gets reset to 7
roundButton.height

I hope that helps,

Mike

PS: Thanks to the awesome resources on Team Treehouse, I launched my first app.

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