Swift - Initializing class variables which are classes

Question

I am new to Swift. I am having trouble with declaring classes. I have the following -

class position_ 
{
    var x: Float = 0
    var y: Float = 0
}

class node_
{
    var label: String = nil
    var coordinates: position_
}

Now I can create an initializer init() in the position_ class, like this -

class position_ 
{
    var x: Float
    var y: Float
    init()
    {
        x = 0
        y = 0
    }
}

Is there anyway I can use this initializer in the node_ class? Because, without an init() function there is no way to initialize the coordinates variable in the node_ class. Or is there?
I find it hard to believe that Swift would require me to initialize each of the position_ variables again in the node_ class. In other words is there a better option than the below one?

class node_
{
    var label: String
    var coordinates: position_
    init()
    {
        name = nil
        coordinates.x = 0
        coordinates.y = 0
    }
}

Also if I want to create another variable say "b" of type UIButton how do I initialize that? That is really what I want to do.

mikem · Accepted Answer · 2016-06-21 06:40:44Z

You don't have to initialize every variable again because each time you create new instance of a class, structure or enumeration, their stored properties have initial value.
Always try to provide a default value rather then setting a value within an initializer. If a class or structure provides default values for all its properties Swift automatically gives you a default initializer.
```
class Position {  
    var x: Float = 0   
    var y: Float = 20  
}

let position = Position() // nice!
```
Position class is a very simple data construct - it feels like the Struct type would fit better here.

Final code - with UIButton

struct Position {  
    var x: Float = 0  
    var y: Float = 20  
}

class Node {  
    var label = "" // label is inferred to be of type String  
    var coordinates = Position()  
    var button = UIButton(type: .InfoDark)  
}

let myNode = Node()

Nirav D · Accepted Answer · 2016-06-21 04:48:04Z

0

First every class name Start with capitalize character. So change your node_ class like this

class Node
{
    var label: String
    var coordinates: position_
    init()
    {
        name = ""
        coordinates = position_()
    }
}

Also change your class position_ with Position.
Instead of using _ try to write class name in capitalize first character of each word like this PositionMarker.
Hope this will help you.

answered Jun 21, 2016 at 4:48

Nirav D

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