基类
//基类
class Vehicle {
var currentSpeed = 0.0
var description: String {
return "traveling at \(currentSpeed) miles per hour"
}
func makeNoise() {
}
//阻止重写final
final func stop() {
print("stoped")
}
}
继承
//继承
class Bicycle : Vehicle {
var hasBasket = false
}
方法重写 override
class Train: Vehicle {
//方法重写
override func makeNoise() {
print("hu wu! hu wu!")
}
}
属性重写 override
class Car: Vehicle {
var gear = 1
//属性重写
override var description: String {
return super.description + " in gear \(gear)"
}
}
let bicycle = Bicycle()
bicycle.hasBasket = true
bicycle.currentSpeed = 15.0
print(bicycle.description)
//traveling at 15.0 miles per hour
let train = Train()
train.makeNoise()
//hu wu! hu wu!
let car = Car()
print(car.description)
//traveling at 0.0 miles per hour in gear 1
