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iOS

jon kelson
jon kelson
5,149 Points
Posted by jon kelson
jon kelson
5,149 Points

explain init methods in basic terms please

Hi Please could someone explain init methods a little clearer please . I did the 1st swift coarse and thought I understood until I started swift.2 object oriented swift ! .

many thanks

2 Answers

Alexander Smith
Alexander Smith
10,476 Points
Alexander Smith
Alexander Smith
10,476 Points

Yea I remember that one. Well its the same concept just a lot more thrown in and it involve two classes. The way I went to understand it was just by thinking it as a chain just like any other, just a really long one lol. I just went into xCode and clicked on each part making it underline to where it linked to but ill elaborate.

struct Point {
    let x : Int
    let y : Int

    // initializer
    init(x: Int, y: Int) {
        self.x = x
        self.y = y
    }

K heres your Point class that let position uses and...

class Tower {
    let position: Point
    var range: Int = 1
    var strength: Int = 1

    init(x: Int, y: Int) {
        self.position = Point(x: x, y: y)
    }
}

Part of the Tower class. Just like before, self.position is linked to let position: Point in Tower class. Then since position is of type Point you gotta write that like an instance of type Point. Point is written like Point(x: Int, y: Int) but since you gotta link it to your init you go one step further. x and y in your init is linked to x and y standing in for Int values in Point.

I know its a mouthful but thats what it boils down to. I used xCode to work it out in my head better

jon kelson
jon kelson
5,149 Points
jon kelson
jon kelson
5,149 Points

Thanks very much Alex . That's helped me to understand it better . Thanks

Just one last question if you don't mind . Is this point struct used a lot in this type of game concept when people make games ? Or is it just something treehouse has made up ?

Alexander Smith
Alexander Smith
10,476 Points
Alexander Smith
Alexander Smith
10,476 Points

To my understanding this is the basic object for a point. I have seen it in a couple places when making anything that relies on a coordinate plane. It can be expanded for the z plane as well for 3D

Alexander Smith
Alexander Smith
10,476 Points
Alexander Smith
Alexander Smith
10,476 Points

An init method is basically used to create a template to use when creating an instance. Example...

class Example {
   var name: String

   init(name: String){
      self.name = name
   }
}

So in this Example class we have one var to initialize. I like to think of init methods as links in a chain. The self.name is linked to var name: String. name that self.name = , is linked to name in the init parameter. when you create an instance of Example class you do it like this...

let ex = Example(name: "Alex")

This parameter is a direct reflection of your init method. Your init method is what you use to create an instance. Objects like a struct is given a default init so you dont need to write one

jon kelson
jon kelson
5,149 Points
jon kelson
jon kelson
5,149 Points

thanks Alex , sorry should have said Its more this sort of Init that was confusing me in swift.2 object oriented swift .

Many thanks

class Tower {

let postion: Point
var range : Int = 1
var strength: Int = 1

init(x: Int, y: Int) {
self.postion = Point(x: x, y: y)