Question

我刚修改过它。另一个问题是，如果我想从BaseParticipant继承子类，我可以在子类中重新实现func performEvent吗？例如：

class CyclingParticipant: BaseParticipant, Participant
{
init(name: String)
{
    super.init(name: name, preferredEvent: Event.CYCLING)

}

func performEvent(event: Event, distance: Distance) throws
{

}

}

但是编译器说＆＃34; CyclingParticipant与协议参与者的冗余一致性。

class BaseParticipant: Participant
{
 var name: String
 var preferredEvent: Event
 var raceTime: Int
 var couldNotFinish: Bool
 //var performedEvent: Event
// in swift, the class accepts protocol must impletment all funcs inside protocol

init(name: String, preferredEvent: Event)
{
    self.name = name
    self.preferredEvent = preferredEvent
    self.raceTime = 0
    self.couldNotFinish = false
}

func getName() -> String
{
    return self.name
}

func getPreferredEvent() -> Event
{
    return self.preferredEvent
}

func isDisqualified() -> Bool
{
    return self.couldNotFinish
}

func addTime(addtionalRaceTime:Int) -> Void
{
    self.raceTime += addtionalRaceTime
}

func setCouldNotFinish() -> Void
{
    self.couldNotFinish = true
}
func performEvent(event: Event, distance: Distance) throws -> Int
{
    return 1
}
func getTime() throws
{

}

}

协议代码参与者：

protocol Participant
{
func getName() -> String
func getPreferredEvent() -> Event
func isDisqualified() -> Bool
func performEvent(event: Event,distance: Distance) throws ->Int
func addTime(addtionalRaceTime: Int)
func setCouldNotFinish()
func getTime() throws

}

Answer 1

您错过了协议中列出的getTime()函数的实现。另外，你应该在Piazza上发布这样的问题。：P

[更新以回答重写问题]

BaseParticipant类已经采用Participant协议，因此CyclingParticipant子类不应声明它也采用它，这会导致冗余一致性错误。由于BaseParticipant已经是Participant，因此BaseParticipant的任何子类也都是Participant。

变化：

class CyclingParticipant: BaseParticipant, Participant

为：

class CyclingParticipant: BaseParticipant

Answer 2

默认情况下，需要Swift协议中的所有声明方法。

var db = database.GetCollection<BsonDocument>("cars"); FieldDefinition<BsonDocument, string> field = "car.manufacture"; FilterDefinition<BsonDocument> filter = new BsonDocument(); var a = db.DistinctAsync(field, filter).GetAwaiter().GetResult().ToListAsync().GetAwaiter().GetResult();未实施

我可以在子类中实现协议的一个功能吗？

2 个答案: