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 才是正确的。origin.y是一个控件的初始y坐标加上控价高的一半才是控件的中心y点。
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
如果子类实现了父类所有的构造函数,则继承了父类所有的便利函数,
如果子类未继承父类任何一个构造函数,则会继承父类所有的便利函数。
如果子类未继承父类任何一个构造函数,则会继承父类所有的便利函数。
2016-11-30