Swift 常用标准库协议
发布时间:2020-12-14 06:25:33 所属栏目:百科 来源:网络整理
导读:struct Size: Equatable,Comparable,CustomStringConvertible { // 相等的协议 var width: Double var height: Double var description: String { return "witth:" + "(self.width)" + " " + "height" + "(self.height)" }}// 相等协议的实现func ==(left:
struct Size: Equatable,Comparable,CustomStringConvertible { // 相等的协议 var width: Double var height: Double var description: String { return "witth:" + "(self.width)" + " " + "height" + "(self.height)" } } // 相等协议的实现 func ==(left: Size,right: Size) -> Bool { return left.height == right.height && left.width == right.height } // 比较协议的实现 func <(left: Size,right: Size) ->Bool { if left.width * left.height != right.height * right.width { return left.width * left.height < right.height * right.width } return left.width * left.height > right.height * right.width } 扩展协议 protocol student:CustomStringConvertible { var name: String{get} var height: Double {get} } // 扩展协议,在协议扩展中可以添加具体的逻辑 extension student { var description: String { return "name is" + " (name)" + " " + "height is" + " (height)" } func showInfo() { print("good student") } } // 扩展协议 CustomStringConvertible extension CustomStringConvertible { var descriptionWithDate:String { return NSDate().description + " " + description } } class Person: student { var name: String = "" var height: Double = 0.0 init(name: String,height: Double) { self.name = name self.height = height } } var person = Person(name: "jobs",height: 1.80) print(person) person.showInfo() print(person.descriptionWithDate)
name is jobs height is 1.8 good student 2017-02-24 08:57:15 +0000 name is jobs height is 1.8
对已有的协议修改 protocol Student: CustomStringConvertible { var name: String{get} var height: Double {get} } // 扩展协议,在协议扩展中可以添加具体的逻辑 extension Student { var description: String { return "name is" + " (name)" + " " + "height is" + " (height)" } func showInfo() { print("good student") } } protocol HighSchoolStudent { var age: Int {get} } // 对已有的协议做修改 当类准守HighSchoolStudent的协议时 打印 good HighSchoolStudent extension Student where Self:HighSchoolStudent { func showInfo() { print("name is" + " (name)" + " " + "height is" + " (height)" + " " + "age is " + "(age)") } } // 扩展协议 CustomStringConvertible extension CustomStringConvertible { var descriptionWithDate:String { return NSDate().description + " " + description } } class Person: Student { var name: String = "" var height: Double = 0.0 init(name: String,height: Double) { self.name = name self.height = height } } class People: Student,HighSchoolStudent { internal var height: Double = 0.0 internal var name: String = "" internal var age: Int = 0 init(height:Double,name: String,age: Int) { self.name = name self.age = age self.height = height } } var person = Person(name: "jobs",height: 1.80) print(person) person.showInfo() print(person.descriptionWithDate) var people = People(height: 1.7,name: "zhangsan",age: 17) people.showInfo() 上面代码打印结果: name is jobs height is 1.8 good student 2017-02-24 09:44:12 +0000 name is jobs height is 1.8 name is zhangsan height is 1.7 age is 17 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |