// 类是一种引用类型 class Person { var firstName: String var lastName: String // 构造函数 init(firstName: String,lastName: String) { self.firstName = firstName self.lastName = lastName } func fullName() -> String { return self.firstName + " " + self.lastName } } var person1 = Person(firstName: "Steve",lastName: "Jobs"); var person2 = person1 person1 === person2 // 判断两个实例是否相等用===,不能用==, == 来判断值类型
什么时候用结构体,什么时候用类
把结构体看作值的时候,比如温度,经纬,坐标。。。
把类看作物体的时候。比如人,动物,车。。。
结构体是值类型,类是引用类型,类是可以被继承的,结构体比类更加的轻量级
看下面的例子
struct Point { var x = 0.0 var y = 0.0 } struct Size { var width = 0.0 var height = 0.0 } class Rectangle { // 矩形 var origin = Point() // 远点 var size = Size() // 长宽 var lengthOfSide:Double { // 边长 get { return size.width * 2 + size.height * 2 } } var area:Double { // 面积 get { return size.width * size.height } } var center:Point { // get方法 get { let centerX = origin.x + size.width/2 let centerY = origin.y + size.height/2 return Point(x: centerX,y: centerY) } // set方法 set { origin.x = newValue.x - size.width/2 origin.y = newValue.y - size.height/2 } } // 构造方法 init(origin: Point,size: Size) { self.origin = origin; self.size = size } } var rect = Rectangle(origin: Point(x: 0,y: 0),size: Size(width: 10,height: 10)) rect.center = Point(x: 10,y: 10) print(rect.origin) print(rect.lengthOfSide) print(rect.area)上面打印结果:
Point(x: 5.0,y: 5.0)
40.0
100.0
class Player { static var highestscore = 0 // 静态属性记录所有玩家的最高分 var name:String var score:Int = 0 init(name: String) { self.name = name } // 静态方法 类方法 static func getPlayerHighestscore() -> Int { return Player.highestscore } func play() -> Void { let score = (Int)(arc4random() % 99) print("\(name) palyer is get socre \(score)") self.score += score print("total score of \(name) is \(self.score)") if score > Player.highestscore { Player.highestscore = score print("Player highestscore is \(Player.highestscore)\n"); } } } var player1 = Player(name: "player1") player1.play() player1.play() print("static method Player highestscore is \(Player.getPlayerHighestscore())\n")上面打印结果:
player1 palyer is get socre 87
total score of player1 is 87
Player highestscore is 87
player1 palyer is get socre 29
total score of player1 is 116
static method Player highestscore is 87