Swift－实例方法

「爱情、让人受尽委屈。」 2023-10-17 09:43 52阅读 0赞

实例方法

/*
     1、实例方法
     */
    print("1、实例方法")
    class MyPoint {
        var myX:Double = 0.0
        var myY:Double = 0.0
        
        func setPoint(x:Double,y:Double) {
            myX = x
            myY = y
        }
        func showPoint(){
            print("x=\(myX),y=\(myY)")
        }
    }
    func setPoint(x:Double,_ y:Double) {
    }
    //默认第一参数作为内部参数，第二个及以后既作为内部有作为外部参数
    setPoint(x:10.0,10.0)
    var p0 = MyPoint()
    p0.setPoint(x: 5.0, y: 5.0)
    p0.showPoint()
    
    /*
     2、mutating方法
     值类型（结构体或者枚举）默认方法是不可以修改属性的，如果要修改要使用mutating关键字
     */
    print("\n2、mutating方法")
    struct Myperson {
        var name:String = ""
        var age:Int = 0
        mutating func set(name:String,age:Int) {
            self.name = name
            self.age = age
        }
        func show() {
            print("name=\(name),age=\(age)")
        }
    }
    var person = Myperson()
    person.set(name: "ming", age: 20)
    person.show()
    
    enum LightSwitch {
        case OFF,LOW,HIGH
        mutating func next(){
            switch self {
            case .OFF:
                self = .LOW
            case .LOW:
                self = .HIGH
            case .HIGH:
                self = .OFF
            }
        }
    }
    var light = LightSwitch.LOW
    light.next()
    print("light=\(light)")
    
    /*
     3、类型方法
     通过类名来调用的方法，就像类型属性一样
     类方法对应的关键字是static（结构体和枚举）class（类）
     类方法里面不存在self
     */
    
    //struct TypeMethods {
    //    var p:Int = 0
    //    static var sp:Int = 0
    //    func method() {
    //        print("p=\(p),sp=\(TypeMethods.sp)")
    //    }
    //    static func staticMethod(){
    //        print("sp=\(TypeMethods.sp)")
    //    }
    //}
    
    print("\n3、类型方法")
    class TypeMethods {
        var p:Int = 0
        class var sp:Int {
            return 10
        }
        func method() {
            print("p=\(p),sp=\(TypeMethods.sp)")
        }
        class func staticMethod(){
            print("sp=\(TypeMethods.sp)")
        }
    }
    var type = TypeMethods()
    type.method()
    TypeMethods.staticMethod()
    
    /*
     4、subscript方法   实例对象[索引]调用
     */
    print("\n4、subscript方法")
    struct Student {
        var name:String = ""
        var math:Int = 0
        var chinese:Int = 0
        var english:Int = 0
        func sorce(cource:String) -> Int? {
            switch cource {
            case "math":
                return math
            case "chinese":
                return chinese
            case "english":
                return english
            default:
                return nil
            }
        }
        subscript (cource:String) -> Int? {
            get{
                switch cource {
                case "math":
                    return math
                case "chinese":
                    return chinese
                case "english":
                    return english
                default:
                    return nil
                }
            }
            set{
                switch cource {
                case "math":
                    math = newValue!
                case "chinese":
                    chinese = newValue!
                case "english":
                    english = newValue!
                default:
                    print("key is wrong")
                }
            }
        }
    }
    var student1 = Student(name:"ming",math:98,chinese:97,english:100)
    student1["math"] = 96
    print(student1["math"]!)
    print(student1.sorce(cource:"chinese")!)
    
    /*
     5、多索引subscript方法   实例对象[索引]调用
     */
    print("\n5、多索引subscript方法")
    struct Multiple {
        subscript (a:Int,b:Int) -> Int{
            return a*b
        }
    }
    var mul = Multiple()
    print(mul[3,5])