Swift_继承

//1基类class Father {        var pen = 0.0    func read() {                print("父类的新闻")    }}//2子类class Sun_M: Father {        var sunPen = 0    override func read() {                print("子类的新闻")    }        var name:String{                return "SANG"    }        var money:Int{                return sunPen    }}//3继承子类的新派生类class Friend: Sun_M {        override var name: String{                return super.name+"SONG"    }    }//4重写属性观察器,class Sales:Sun_M {        override var sunPen: Int{                didSet{            pen = Double(sunPen)+1            print("pen \(pen)")        }            }}//5防止重写class finalClass{        final var applePen = 1    final func test(){            }        final class func test2(){            }    }class finalSub: finalClass {        //无法重写基类 定义了 final 的属性和函数}import UIKitclass ViewController: UIViewController {    override func viewDidLoad() {        super.viewDidLoad()        //1基类使用        var fat = Father()        fat.read()        //打印 ：v父类的新闻                                //2子类使用        var sun = Sun_M()        sun.read()        //打印 ：子类的新闻                        //3子类的派生类        var fri = Friend()        fri.pen = 10.1        fri.sunPen = 99        print(fri.name)        //打印 ：SANGSONG                                //4属性观察器        var sal = Sales()        sal.sunPen = 33        sal.sunPen = 33        sal.sunPen = 1        sal.sunPen = 3        //打印: pen 34.0 pen 34.0 pen 2.0 pen 4.0                        //5防止重写            }}