Learning swift--Methods

Method

A method is a function that is associated with some particular type. classes, structs, enumerations can define instance methods , and instance methods encapsulate specific tasks and functions for instances of a given type. classes, structs, enumerations can also define type methods , and type methods are associated with the type itself. Type methods are similar to class methods in Objective-c.

instance Method

Class Counter {    var count = 0        //Implement two simple methods    func increment () {        count + = 1    }        func IncrementBy (AMO Unt:int) {        count + = Amount    }}let counter = Counter () counter.increment () print (counter.count)// Print out: 1counter.incrementby (5) print (Counter.count)//Print out: 5

Self Property

You do not usually need to use the Self property, but in some methods the parameter name is the same as a property name, you need to use the Self property, the main function is to distinguish the property name

struct Point {    var x = 0.0, y = 0.0    func ISTOTHERIGHTOFX (x:double), Bool {        ////////when the argument (x) is passed in to match the declared property Use the Self property to differentiate        return self.x > x    }}let point = Point (x:5.0, y:3.0) if POINT.ISTOTHERIGHTOFX (1.0) {    print ("T He point was to the right of the line where x = = 1.0 ")}

instance methods modify value types

Structs and enumerations are value types, so modifying the properties of a value type using an instance method requires special handling, otherwise it cannot be modified

struct Point {    var x = 0.0, y = 0.0        //If you want to modify the value type property, you need to add the "mutating" keyword    mutating func movebyx (deltax:double, Del tay:double) {        self.x + = deltax Self.y + =        DeltaY        //self = Point        (x:x + deltax, y:y + deltay)  so write Effect    }}var point = Point (x:5.0, y:3.0) Point.movebyx (8.0, deltay:2.0) print (point)

Enum Stateswitch {case-    Off, Low, high    mutating func next () {switch-Self        {case        . Off: Self            =. Low Case        . Low: Self            =. High Case        . High: Self            =. Off        }    }}var ovenlight = StateSwitch.OffovenLight.next ()//is now Low state ovenlight.next ()//is now high state

Type Method

An instance method is a method that is called by an instance of the type. You can also define a method called by the type itself, which is called a type method . declares struct and enum type methods, plus keywords before the method's keywords func static . Class may use keywords class to allow subclasses to override the implementation of the parent class.

Class SomeClass {    class func SomeFunc (), SomeClass {        return SomeClass ()    }}//type method can be called directly using type without creating an instance let SomeClass = Someclass.somefunc () struct SomeStruct {    static func SomeFunc () {            }}somestruct.somefunc ()

Learning swift--Methods