<aside> 🌻 只有类有析构器，枚举和结构体都没有，因为它们是值类型。

</aside>

每个类只能有一个析构器，且不接收任何参数，也没有小括号，后面直接接一个大括号，不能手动调用析构器！父类的析构器会被自动调用！

deinit {
    // 执行析构过程
}

析构器实践

class Bank {
    static var coinsInBank = 10_000
    static func distribute(coins numberOfCoinsRequested: Int) -> Int {
        let numberOfCoinsToVend = min(numberOfCoinsRequested, coinsInBank)
        coinsInBank -= numberOfCoinsToVend
        return numberOfCoinsToVend
    }
    static func receive(coins: Int) {
        coinsInBank += coins
    }
}

class Player {
    var coinsInPurse: Int
    init(coins: Int) {
        coinsInPurse = Bank.distribute(coins: coins)
    }
    func win(coins: Int) {
        coinsInPurse += Bank.distribute(coins: coins)
    }
    deinit {
        Bank.receive(coins: coinsInPurse)
    }
}

var playerOne: Player? = Player(coins: 100)
print("A new player has joined the game with \\(playerOne!.coinsInPurse) coins")
// 打印“A new player has joined the game with 100 coins”
print("There are now \\(Bank.coinsInBank) coins left in the bank")
// 打印“There are now 9900 coins left in the bank”

playerOne!.win(coins: 2_000)
print("PlayerOne won 2000 coins & now has \\(playerOne!.coinsInPurse) coins")
// 打印“PlayerOne won 2000 coins & now has 2100 coins”
print("The bank now only has \\(Bank.coinsInBank) coins left")
// 打印“The bank now only has 7900 coins left”

playerOne = nil
print("PlayerOne has left the game")
// 打印“PlayerOne has left the game”
print("The bank now has \\(Bank.coinsInBank) coins")
// 打印“The bank now has 10000 coins”