Inheritance

Swift classes do not inherit from a universal base class. Classes you define without specifying a superclass automatically become base classes for you to build upon.

class Car: Vehicle {
    var speed: Double = 0.0
    init() {
        super.init()
        maxPassengers = 5
        numberOfWheels = 4
    }
    override func description() -> String {
        return super.description() + "; "
            + "traveling at (speed) mph"
    }
} 

You can present an inherited read-only property as a read-write property by providing both a getter and a setter in your subclass property override. You cannot, however, present an inherited read-write property as a read-only property.

You can prevent a method, property, or subscript from being overridden by marking it as final