swift学习－ 嵌套类型（二十）

//21点点例子

struct BlackjackCard {

    //潜逃定义枚举类型Suit

    enum Suit: Character {

        case Spades = "♠️", Hearts = "♥️", Diamonds = "♦️", Clubs = "♣️"

    }

    //定义潜逃枚举Rank

    enum Rank: Int {

        case Two = 2, Three, Four, Five, Six, Seven, Eight, Nine, Ten

        case Jack, Queen, King, Ace //rawValue为:11,12,13,14

        struct Values {

            let first:Int, second: Int?

        }

        var values:Values {

            switch self {

                case .Ace:

                return Values(first: 1, second: 11)

            case .Jack, .Queen, .King:

                return Values(first: 10, second: nil)

            default:

                return Values(first: self.rawValue, second: nil)

            }

        }

    }

    let rank:Rank, suit: Suit

    var description: String {

        var output = "suit is \(suit.rawValue),"

        output += " value is \(rank.values.first)"

        //访问values计算型属性

        if let second = rank.values.second {

            output += " or \(second)"

        }

        return output

    }

}

//结构体默认构造器 BlackjackCard.Rank.Ace 可以写成 .Ace (swift推断类型)

let theAceOfSpades = BlackjackCard(rank: .Ace, suit: .Spades)

print(theAceOfSpades.rank)

print("theAceOfSpades: \(theAceOfSpades.description)")

//theAceOfSpades: suit is ♠️, value is 1 or 11

let heartsSymbol = BlackjackCard.Suit.Hearts.rawValue

print(heartsSymbol)

//♥️