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iOS Object-Oriented Swift Inheritance Inheritance and Initializers

Why width:width and height:height? What is the idea behind this?

I need a bit of clarification on this one...

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

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

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

class RoundButton: Button {
  var cornerRadius: Double = 5.0

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

1 Answer

Enara L. Otaegi
Enara L. Otaegi
13,107 Points

When you make an instance of RoundButton you do it like this:

let roundButton = RoundButton(width: 14, height: 5, cornerRadius: 2)

So the RoundButton init method takes 14 and 5 in variables named width and height and pass them to the super.init method.

super.init(width: width //this is the 14 stored in a variable called width and the same goes for height