let result = withdraw(amount: 300)
switch result {
case .success(let newBalance):
print("\(newBalance)元剩余")
case .error(let errorMessage):
print(errorMessage)
}
switch result {
case .success(let newBalance):
print("\(newBalance)元剩余")
case .error(let errorMessage):
print(errorMessage)
}
2016-12-22
最新回答 / RaymanZhi
centerY = origin.y + size.height/2 ?才是正確的。origin.y是一個控件的初始y坐標加上控價高的一半才是控件的中心y點。
2016-12-20
swift3.0
let commaIndex = coordinateString.range(of: ",")!.lowerBound
let firstElement = coordinateString.substring(to: commaIndex)
let secondElement = coordinateString.substring(from:coordinateString.index(after: commaIndex) )
let commaIndex = coordinateString.range(of: ",")!.lowerBound
let firstElement = coordinateString.substring(to: commaIndex)
let secondElement = coordinateString.substring(from:coordinateString.index(after: commaIndex) )
2016-12-15
如果子類實現了父類所有的構造函數,則繼承了父類所有的便利函數,
如果子類未繼承父類任何一個構造函數,則會繼承父類所有的便利函數。
如果子類未繼承父類任何一個構造函數,則會繼承父類所有的便利函數。
2016-11-30