编辑代码

enum OperationFeedback {
    case Done(currentBalance: Int) 
    case Fail(warningInfo: String)
}
var balanceOfATM = 10000
func withdrawFromATM(amount:Int) -> OperationFeedback{
    if balanceOfATM <= amount {
        balanceOfATM -= amount
        return .Done(currentBalance:balance0fATM)
    } else {
        return .Fail(warningInfo: "Balance is not enough!" )
    }
}
var getMoney = withdrawFromATM(amount:1288)
switch getMoney {
case .Done(let currentBalance):
    print("Operation is successful. The current balance is \(currentBalance)") 
case .Fail(let warningInfo):
    print(warningInfo)
}