CODEWITHSUNDEEP
swift
William Hu
William Hu

Reputation: 16149

swift init properties with self or not?

I saw the code blow from swift 2.0 init method, Square is a subclass from NamedShape, 1. do i need to add a self.property or just use without self ? 2. Does it means properties before super.init(name: name) use self, and after not?

class Square : NamedShape {
    init(sideLength: Double, name: String) {
            self.sideLength = sideLength
            super.init(name: name)
            numberOfSides = 4 //Add self. or not
       }
}

and 

init(sideLengt: Double, name: String) {
        sideLength = sideLengt //without self. , is it right?
        super.init(name: name)
        self.numberOfSides = 4
    }

Upvotes: 1

Views: 1020

Answers (2)

ViTUu
ViTUu

Reputation: 1204

You can use without self, but the field variable need be different than outside variable.

Why?

Simple, variables in field is constant statement (let) init(sideLength: Double, name: String) sideLenght and name in this line are constants variables, because this you can't set new value for it.

ps. let in swift is same than const in other language

Ex.

example why can't use same name without self

The correct way to implement is with self., because in this case we tell to compiler to set the variable outside in our class.

example using variable with self

Other example now setting variable without self., look next image, we can use without self because it is outside variable.

example using name without self

Upvotes: 2

Korpel
Korpel

Reputation: 2458

you use the keyword self.name when you are referring to the name is outside of the init. it's more to recognise what name you are referring to if you use the same argument "name" as your init parameter

here is an example

var name : String

init(name : String)//here we have the same name with the value above
{
self.name = name//self.name is the variable outside of the init and now we are making that value the same with the value used in init
}

Upvotes: 1

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