2019년 1월 8일 화요일

Inheritance

 Swift Programming Language Guide: Inheritance, 코드 부분

// Defining a Base Class



class Vehicle {

   var currentSpeed = 0.0
   var description: String {
       return "traveling at \(currentSpeed) miles per hour"
   }
   func makeNoise() {
   }
}

let someVehicle = Vehicle()
print("Vehicle: \(someVehicle.description)")


// Subclassing

class Bicycle: Vehicle {
   var hasBasket = false
}

let bicycle = Bicycle()
bicycle.hasBasket = true

bicycle.currentSpeed = 15.0
print("Bicycle: \(bicycle.description)")

class Tandem: Bicycle {
   var currentNumberOfPassengers = 0
}

let tandem = Tandem()
tandem.hasBasket = true
tandem.currentNumberOfPassengers = 2
tandem.currentSpeed = 22.0
print("Tandem: \(tandem.description)")


// Overriding

class Train: Vehicle {
   override func makeNoise() {
       print("Choo Choo")
   }
}

let train = Train()
train.makeNoise()

class Car: Vehicle {
   var gear = 1
   override var description: String {
       return super.description + "in gear \(gear)"
   }
}

let car = Car()
car.currentSpeed = 25.0
car.gear = 3
print("Car: \(car.description)")

class AutomaticCar: Car {
   override var currentSpeed: Double {
       didSet {
           gear = Int(currentSpeed / 10.0) + 1
       }
   }
}

let automatic = AutomaticCar()
automatic.currentSpeed = 35.0
print("AutomaticCar: \(automatic.description)")