20.嵌套类型

嵌套类型的定义位置与使用

struct Cards {
    let num:CardNum
    let suit:CardSuit
    enum CardNum:Int { // 类型嵌套
        case ace = 1,two,three,four,five,six,seven,eight,nine,ten
        case jack,queen,king
    }
    enum CardSuit:Character {
        case spades = "♠", hearts = "♡", diamonds = "♢", clubs = "♣"
    }
}
var card = Cards.init(num: .ace, suit: .hearts)// 嵌套类型可以通过上下文推导，直接调用
print(Cards.CardSuit.hearts.rawValue)// 外部引用嵌套类型时，需要在类型前加入外部类型前缀