learn about the swift type enum and its usage, hash value, raw value

swift_learn_05.swift

//enum

enum Rank :Int{
    case Ace = 1
    case Two, Three, Four, Five, Six, Seven, Eight, Nine, Ten
    case Jack, Queen, King
    
    func desc() -> String{
        switch self{
        case .Ace:
            return "ace"
        case .Jack:
            return "jack"
        case .Queen:
            return "queen"
        case .King:
            return "king"
        default:
            return String(self.rawValue)
        }
    }
    
}

let ace=Rank.Ace
let aceRawValue=ace.rawValue
let aceDesc=ace.desc()

let nine=Rank.Nine
let nineRawValue=nine.rawValue
let nineDesc=nine.desc()


func enumCmp(e1 :Rank, e2 :Rank) -> Int{
    return e1.rawValue - e2.rawValue
}

var cmpResult=enumCmp(ace, nine)
if cmpResult==0{
    println("\(ace.desc()) equal to \(nine.desc())")
}else if cmpResult>0{
    println("\(ace.desc()) bigger than \(nine.desc())")
}else{
    println("\(ace.desc()) smaller than \(nine.desc())")
}

let eight=Rank(rawValue : 8)
println(eight)

if let sevenRank = Rank(rawValue: 7){
    let sevenDesc=sevenRank.desc()
    println(sevenDesc)
}

//enum hash value is the logic index
//enum raw value is defined by the raw type
//enum no specified raw value follows the hash value
//enum hash value is int

enum Suit :Float{
    case Spades
    case Hearts, Diamonds, Clubs
    
    func desc()->String{
        switch self{
        case .Spades:
            return "spades"
        case .Hearts:
            return "hearts"
        case .Diamonds:
            return "diamonds"
        case .Clubs:
            return "clubs"
        }
    }
}


let hearts=Suit.Hearts
println(hearts.hashValue)
println(hearts.rawValue)
println(hearts.desc())

let diamonds=Suit.Diamonds
println(diamonds.hashValue)
println(diamonds.rawValue)
println(diamonds.desc())

//enum raw type can be of any type
enum Day : String{
    case Monday="Monday"
    case Tuesday="Tuesday"
    case Wednesday="Wednesday"
    case Thursday="Thursday"
    case Friday="Friday"
    case Saturday="Saturday"
    case Sunday="Sunday"
    
    func desc()->String{
        return "\(self.hashValue)\t\(self.rawValue)"
    }
}

var fri=Day.Friday
println(fri.desc())