Swift学习笔记类的继承重载与构造函数

class Vehicle {
    var numberOfWheels: Int
    var maxPassengers: Int
    func description() -> String {
        return String(numberOfWheels)
    }
    init(){
        numberOfWheels = 0
        maxPassengers = 1
    }
}

let someVehicle = Vehicle()

class Bicycle: Vehicle {
     override init() {
        super.init()
        numberOfWheels = 2
    }
}

let bicycle = Bicycle()
bicycle.description()

class Car: Vehicle {
    var speed: Double = 0.0
    override init() {
        super.init()
        maxPassengers = 5
        numberOfWheels = 4
    }
    override func description() -> String {
        return super.description()
    }
}
let car = Car()

class SpeedLimitedCar: Car {
    override var speed: Double{
        get {
            return super.speed
        }
        set {
            super.speed = min(newValue, 40.0)
        }
    }
}

let limitedCar = SpeedLimitedCar()
limitedCar.speed = 60.0

class AutomaticCar: Car {
    var gear = 1
    final var name:String = ""
    override var speed: Double{
        didSet{
            gear = Int(speed / 10.0) + 1
        }
    }
    override func description() -> String {
        return super.description()
    }
}
let automatic = AutomaticCar()
automatic.speed = 35.0


struct  Color {
    var red = 0.0, green = 0.0, blue = 0.0
    init(red: Double, green: Double, blue: Double){
        self.red = red
        self.green = green
        self.blue = blue
    }
}
let magenta = Color(red: 1.0, green: 0.0, blue: 1.0)

class SurveyQuestion {
    let text: String
    var response: String?
    init(text: String){
        self.text = text
    }
    func ask() {
        println(text)
    }
}

let cheeseQuestion = SurveyQuestion(text: "DO you like cheese?")
cheeseQuestion.ask()
cheeseQuestion.response = "Yes, I do like cheese."

class ShoppingListItem {
    var name: String?
    var quantity = 1
    var purchased = false
}
var item = ShoppingListItem()
struct Size {
    var width = 0.0, height = 0.0
}
let twoByTwo = Size(width: 2.0, height: 2.0)


struct CheckerBoard {
    let boardColors: [Bool] = {
        var temporaryBoard = [Bool]()
        var isBlack = false
        for i in 1...10{
            for j in 1...10{
                temporaryBoard.append(isBlack)
                isBlack = !isBlack
            }
            isBlack = !isBlack
        }
        return temporaryBoard
    }()
}
let board = CheckerBoard()

class Timer {
    var str = "strart"
    deinit{
        str = "close"
    }
}

类的重载，构造，析构函数，其中构造比较复杂一点，其他与其他语言无异