// Playground - noun: a place where people can playimport UIKit/***********************************************************//*** 一. A Swift Tour*///1.hello worldvar str = "Hello, playground"println("Hello, world \(str)")//2.返回值为函数的函数func addOne(number: Int) -> Int{    return 1 + number}func makeIncrementer() -> (Int -> Int){    return addOne}var increment = makeIncrementer()increment(7)//3.参数为函数的函数func hasAnyMatches(list: [Int], lessThanTen: Int -> Bool) -> Bool{    for item in list{        if lessThanTen(item){            return true        }    }    return false}func lessThanTen(number: Int) -> Bool{    return number < 10}var numbers = [20, 19, 9, 12]hasAnyMatches(numbers, lessThanTen)//4.函数是一种特殊的闭包，除了大挂号，也可以使用in隔开闭包名和闭包的内容numbers.map({    (number: Int)-> Int in    let result = 3 * number    return result})//4.1 当闭包的类型已知时，闭包可以简写。numbers.map({ number in 3 * number})sort(&numbers) { $0 > $1 }/***********************************************************//***  类对象*///1.定义一个类class Sharp: NSObject {    var numberOfSides: Int = 0    var name: String        init(name: String){//构造方法        self.name = name    }    func simpleDescription() -> String {        return "A sharp with \(numberOfSides) sides"    }}//2.继承, init, override, get, setclass EquilateralTriangle: Sharp {//等边三角形    var sideLength : Double        //3.init方法    init(name: String, sideLength: Double) {        self.sideLength = sideLength        super.init(name: name)        numberOfSides = 3    }        //5.get方法和set方法    var perimeter: Double{//周长        get{            return 3 * sideLength        }        set{            sideLength = newValue / 3.0        }    }        func area() -> Double{        return sideLength * sideLength    }        //4.覆盖    override func simpleDescription() -> String {        return "A EquilateralTriangle with sides of length \(sideLength)."    }}//6. willSet, didSetclass Square: Sharp{    var sideLength: Double    init(name: String, length: Double) {        sideLength = length        super.init(name: name)        numberOfSides = 4    }    override func simpleDescription() -> String {        return "A Square with sides of length \(sideLength)."    }}class traingleAndSquare: Sharp {    var traingle: EquilateralTriangle{        willSet{            square.sideLength = newValue.sideLength        }    }    var square: Square{        willSet{            traingle.sideLength = newValue.sideLength        }    }    init(size: Double, name: String){        square = Square(name: name, length: size)        traingle = EquilateralTriangle(name: name, sideLength: size)        super.init(name: name)    }    }//

// Playground - noun: a place where people can playimport UIKitvar str = "Hello, playground"//定义一个协议protocol ExampleProtocol {    var simpleDescription: String { get }    mutating func adjust()}//类、枚举、结构体都可以使用协议class SimpleClass: ExampleProtocol {    var simpleDescription: String = "A very simple class"    var anotherProperty: Int = 69105    func adjust() {        simpleDescription += " Now 100% adjusted."    }}var a = SimpleClass()a.adjust()let simpleDisc = a.simpleDescription//扩展extension Int: ExampleProtocol {    var simpleDescription: String {        return "The number \(self)"    }    mutating func adjust() {        self += 42    }}//给Double类型扩展一个绝对值属性extension Double {    var absoluteValue :Double {        return self > 0 ? self : -1 * self    }}var d: Double = -203.1println(d.absoluteValue)//范型(Generics)enum OptionalValue<T> {//可选值    case None    case Some(T)}var possibleInt: OptionalValue<Int> = .None//OptionalValue.NonepossibleInt = .Some(100)//OptionalValue.Some(100)