import UIKit

//class Animal {
//    func speak() {
//        print("Animal speak")
//    }
//    subscript(index: Int) -> Int {
//        return index
//    }
//}
//
//var anim: Animal
//anim = Animal()
//anim.speak()
//print(anim[6])
//
//class Cat: Animal {
//    override func speak() {
//        print("Cat speak")
//    }
//
//    override subscript(index: Int) -> Int {
//        return super[index] + 1
//    }
//}
//
//var cat = Cat()
//cat.speak()
//print(cat[6])

class Animal {
    class func speak() {
        print("Animal speak")
    }
    static subscript(index: Int) -> Int {
        return index
    }
}

class Cat: Animal {
    override class func speak() {
        super.speak()
        print("Cat speak")
    }
}

class Circle {
    static var radius: Int = 0
    class var diameter: Int {
        set {
            print("Circle setDiameter")
            radius = newValue / 2
        }
        get {
            print("Circle getDiameter")
            return radius * 2
        }
    }
}

class SubCircle: Circle {
    override class var diameter: Int {
        set {
            print("SubCircle setDiameter")
            super.diameter = newValue > 0 ? newValue : 0
        }
        get {
            print("SubCircle getDiameter")
            return super.diameter
        }
    }
}