编辑代码

func chekGrade(_ grade: Int) -> String {
    switch grade {
        case 90...100:
            return "优秀"
        case 80...89:
            return "良好"
        case 70...79:
            return "中等"
        case 60...69:
            return "及格"
        case 0...59:
            return "不及格"
        default: return "请输入正确的成绩"
    }
}

print(chekGrade(89))
print(chekGrade(50))
print(chekGrade(101))





enum VendingMachineError: Error {
    case invalidSelection                     //选择无效
    case insufficientFunds(coinsNeeded: Int) //金额不足
    case outOfStock                             //缺货
}

struct Item {
    var price: Int
    var count: Int
}

class VendingMachine {
    var inventory = [
        "Candy Bar": Item(price: 12, count: 7),
        "Chips": Item(price: 10, count: 4),
        "Pretzels": Item(price: 7, count: 11)
    ]
    var coinsDeposited = 0

    func vend(itemNamed name: String) throws {
        guard let item = inventory[name] else {
            throw VendingMachineError.invalidSelection
        }

        guard item.count > 0 else {
            throw VendingMachineError.outOfStock
        }

        guard item.price <= coinsDeposited else {
            throw VendingMachineError.insufficientFunds(coinsNeeded: item.price - coinsDeposited)
        }

        coinsDeposited -= item.price

        var newItem = item
        newItem.count -= 1
        inventory[name] = newItem

        print("Dispensing \(name)")
    }
}

var hello = VendingMachine()
hello.coinsDeposited = 10
try hello.vend(itemNamed: "Chips")
print(hello.coinsDeposited)