Swift ProtocolsSwift 프로토콜

protocol Greetable {
    var name: String { get }
    func greet() -> String
}

struct Person: Greetable {
    let name: String
    func greet() -> String { "안녕하세요, (name)입니다!" }
}

// 프로토콜 타입으로 사용
var g: Greetable = Person(name: "Alice")
print(g.greet())

protocol Describable {
    var description: String { get }
}

// 기본 구현 제공
extension Describable {
    func printDescription() {
        print("설명: (description)")
    }
}

// 타입 제약 확장
extension Collection where Element: Comparable {
    func sortedAndFiltered(above threshold: Element) -> [Element] {
        return self.filter { $0 > threshold }.sorted()
    }
}

struct Article: Codable {
    let id: Int
    let title: String
    let published: Bool
    let tags: [String]
}

// JSON 인코딩
let article = Article(id: 1, title: "Swift", published: true, tags: ["ios"])
let data = try JSONEncoder().encode(article)

// JSON 디코딩
let decoded = try JSONDecoder().decode(Article.self, from: data)
print(decoded.title)  // Swift

protocol Container {
    associatedtype Item
    var count: Int { get }
    mutating func append(_ item: Item)
    subscript(i: Int) -> Item { get }
}

struct Stack<Element>: Container {
    private var items: [Element] = []
    var count: Int { items.count }
    mutating func append(_ item: Element) { items.append(item) }
    subscript(i: Int) -> Element { items[i] }
}