枚舉

enum CompassPoint {

? ? case north

? ? case south

? ? case east

? ? case west

}

var directionToHead = CompassPoint.west

directionToHead = .east

遞歸枚舉indirect

indirect enum ArithmeticExpression {

? ? case number(Int)

? ? case addition(ArithmeticExpression, ArithmeticExpression)

? ? case multiplication(ArithmeticExpression, ArithmeticExpression)

}

let five = ArithmeticExpression.number(5)

let four = ArithmeticExpression.number(4)

let sum = ArithmeticExpression.addition(five, four)

let product = ArithmeticExpression.multiplication(sum, ArithmeticExpression.number(2))

func evaluate(_ expression: ArithmeticExpression) -> Int {

? ? switch expression {

? ? case let .number(value):

? ? ? ? return value

? ? case let .addition(left, right):

? ? ? ? return evaluate(left) + evaluate(right)

? ? case let .multiplication(left, right):

? ? ? ? return evaluate(left) * evaluate(right)

? ? }

}

print(evaluate(product))//18

?

轉載于:https://www.cnblogs.com/huoran1120/p/6137942.html

總結

以上是生活随笔為你收集整理的swift--枚举的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。