Swift 3 系列：最佳实践

Swift 3 系列：最佳实践

swift
let maximumNumberOfLoginAttempts = 3
var currentLoginAttempt = 0
currentLoginAttempt += 1
if currentLoginAttempt == maximumNumberOfLoginAttempts {
    print("登录失败次数过多，请稍后再试。")
}

swift
let message = "Hello, World!" // 类型推断为 String
let count = message.count // 类型推断为 Int

swift
var optionalName: String? = "Alice"
if let name = optionalName {
    print("Hello, \(name)!")
} else {
    print("Hello, anonymous!")
}

swift
func divide(_ numerator: Int, by denominator: Int) -> Int? {
    guard denominator != 0 else {
        return nil
    }
    
    return numerator / denominator
}
if let result = divide(10, by: 2) {
    print("结果为：\(result)")
} else {
    print("除数不能为 0")
}

swift
struct Point {
    var x: Double
    var y: Double
}
enum Direction {
    case north
    case south
    case east
    case west
}
var point = Point(x: 0, y: 0)
point.x = 10
var direction = Direction.north
direction = .south

swift
func sayHello(to name: String) {
    print("Hello, \(name)!")
}
let sayGoodbye: (String) -> Void = { name in
    print("Goodbye, \(name)!")
}
sayHello(to: "Alice")
sayGoodbye("Bob")