Initialization Question

I do not know where the code is shown in the book, but it is so strange as an initializer usage example and I guess it's written to demonstrate how Swift initializers can work.

First, the initializer `init(name:numberOfSides:)` of `NamedShape` does not set the value of the property `numberOfSides`, ignoring the argument `numberOfSides`. You should better not write something like this in your actual app.

Maybe this code is intended to show that you have no need to initialize all properties in your class when some properties have initial values.

Second, in the initializer `init(sideLength:name:)` of `Square`, `super.init(name: name, numberOfSides: 1)` is called (though, the value 1 is ignored and the property `numberOfSides` is initialized to 0) and the in the next line, `numberOfSides` is set to 4.

This is ridiculously misleading and hard to read, unless the purpose of the code is telling you that you can modify the value of properties after successful call to super.init .

But with all respects I mentioned above, I'm not sure it is a good example for Swift starters.

Does the book contain the right version of the two classes?

class NamedShape {
    var numberOfSides: Int
    var name: String
    
    init(name: String, numberOfSides: Int) {
        self.name = name
        self.numberOfSides = numberOfSides
    }

    //...
}

class Square: NamedShape {
    var sideLength: Double
    
    init(sideLength: Double, name: String) {
        self.sideLength = sideLength
        super.init(name: name, numberOfSides: 4)
    }

    //...
}

If no, I would not recommend it to starters...

I see. As I wrote in the previous comment, the changes are meaningful if the purpose is to see how initializers work in Swift.

Init in Square (line 20) seems to have overriden the zero initialization on lin 02 without the keyword override?

- Two initializers have different signatures `init(name:)` and `init(sideLength:name:)`

- Your line 20 is just an assignment, not any sort of declaration

You have no need to (and must not) put the keyword override in such cases.

An example when you need override,

if you want to re-declare the property `numberOfSides` as a computed property in Square, you need override.

class Square: NamedShape {
    override var numberOfSides: Int {
        get {
            return 4
        }
        set {
            assert(newValue == 4)
        }
    }
    var sideLength: Double
    
    init(sideLength: Double, name: String) {
        self.sideLength = sideLength
        super.init(name: name)
    }

    //...
}