swift basic

class User {
    let name: String // property
    var score: Int
    // init(name: String, score: Int){
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
    }
    init(){
        self.name = "bob"
        self.score = 30
    }
}
// let tom = User(name: "tom", score: 23)
let tom = User("tom", 23)
print(tom.name)
print(tom.score)

let bob = User()
print(bob.name)
print(bob.score)

計算プロパティ

class User {
    let name: String // property
    var score: Int
    var level: Int{
        get {
            return Int(score / 10)
        }
        set {
            if newValue >= 0 {
                score = newValue * 10
            }
        }
    }
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
    }
    init(){
        self.name = "bob"
        self.score = 30
    }
}

let tom = User("tom", 23)
print(tom.level)
tom.level = 5
print(tom.score)

willSetとdidSet

    let name: String // property
    var score: Int {
        willSet {
            // before change
            print("\(score) -> \(newValue)")
        }
        didSet {
            // after change
            print("Changed: \(score - oldValue)")
            
        }
    }
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
    }
}

let tom = User("tom", 23)
tom.score = 53
tom.score = 40

method

class User {
    let name: String // property
    var score: Int
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
    }
    // クラスに紐付いた関数はメソッド
    func sayHi(msg: String){
        print("\(msg) \(name)")
    }
}
let tom = User("tom", 23)
// tom.sayHi()
tom.sayHi(msg: "hola")

classの継承

class User {
    let name: String // property
    var score: Int
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
    }
    func sayHi(){
        print("hi \(name)")
    }
}

class AdminUser: User {
    func sayHello(){
        print("hello \(name)")
    }
    override func sayHi(){
        print("[admin] hi \(name)")
    }
}
let tom = User("tom", 23)
let bob = AdminUser("bob", 33)
print(bob.name)
print(bob.score)
bob.sayHi()
bob.sayHello()

class User {
    let name: String // property
    var score: Int
    static var count = 0
    init(_ name: String,_ score: Int){
        self.name = name
        self.score = score
        User.count += 1
    }
    func sayHi(){
        print("hi \(name)")
    }
    static func getInfo(){
        print("\(count) instances")
    }
}

User.getInfo()
let tom = User("tom", 23)
User.getInfo()

型キャスト

// asを使った変換　-> 型キャスト
class User {
    let name: String // property
    init(_ name: String){
        self.name = name
    }
}
class AdminUser: User {}

let tom = User("tom")
let bob = AdminUser("bob")

let users: [User] = [tom, bob]

for user in users {
    // if let u = user as? AdminUser{
    //     print(u.name)
    // }
    if user is AdminUser {
        user as! AdminUser
        print(u.name)
    }
}