Question

根据swift.org上的文档，以下是原始源代码：

https://docs.swift.org/swift-book/LanguageGuide/Protocols.html

class DiceGameTracker: DiceGameDelegate {
    var numberOfTurns = 0
    func gameDidStart(_ game: DiceGame) {
        numberOfTurns = 0
        if game is SnakesAndLadders {
            print("Started a new game of Snakes and Ladders")
        }
        print("The game is using a \(game.dice.sides)-sided dice")
    }
    func game(_ game: DiceGame, didStartNewTurnWithDiceRoll diceRoll: Int) {
        numberOfTurns += 1
        print("Rolled a \(diceRoll)")
    }
    func gameDidEnd(_ game: DiceGame) {
        print("The game lasted for \(numberOfTurns) turns")
    }
}

我知道func gameDidStart使用类型DiceGame游戏参数来访问.dice.sides并检查引用对象。

但是func gameDidEnd(_ game: DiceGame)和func game(_ game: DiceGame, didStartNewTurnWithDiceRoll diceRoll: Int) 这两个函数不使用game参数，为什么还要声明它呢？它是Apple的编码样式吗？我真的不明白这部分。。。

Answer 1

简单的答案是肯定的，这是苹果公司的故意选择。该参数是协议方法声明的必需部分：

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因此，为了符合协议，无论是否使用它，它都必须包含参数。

Swift4.2：为什么func gameDidEnd（_ :)无需使用游戏参数，但仍在函数中声明？

1 个答案: