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iOS Object-Oriented Swift Classes and Objects Classes and Their Methods

Mehran Amini Tehrani
Mehran Amini Tehrani
1,523 Points
Posted by Mehran Amini Tehrani
Mehran Amini Tehrani
1,523 Points

Class and methods

We need to provide a means to increase the size of our Button. So we are going to add a method named incrementBy which will accept a parameter named points. (Within the method add points to the width and height properties). How?

Thanks

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 {
        return points = width + points
    }
}

2 Answers

robertvanags
robertvanags
1,760 Points
robertvanags
robertvanags
1,760 Points

If result of your function is some new variable and you want to use it - you have to return it to have it "outside" the function.

Example: you have function named getArea that count area and is receiving height and width from you. Inside this function you have var area = width * height. Now there is new variable area that stores what you need. You have to return it now, if you want to use this area variable in the future.

But in this Button thing, you have to change existing(!!!) 2 variables, so there is no need to return anything. By using this function you just say how to change existing width and height.

As function is used, width and height get new values!

robertvanags
robertvanags
1,760 Points
robertvanags
robertvanags
1,760 Points

You are changing and returning points, but you have to change width and height(these variables have affect on button size) with help of points instead.

You can do it without returning any value.

You can check the code below:

class Button {
  var width: Double
  var height: Double

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

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

}
Mehran Amini Tehrani
Mehran Amini Tehrani
1,523 Points
Mehran Amini Tehrani
Mehran Amini Tehrani
1,523 Points

Thank you, I've done it. But why I do not need to return it?