struct Resolution {

var width = 0

var height = 0

func test(){

println("test")

}

}

//所有结构体都有一个自动生成的成员逐一构造器，用于初始化新结构体实例中成员的属性

let vga = Resolution(width:640,height: 480)

let someResolution = Resolution()

println(vga.width)

println(someResolution.width)

someResolution.test()

//这样写错误

//someResolution.width = 23

class VideoMode {

var resolution = Resolution()

var interlaced = false

var frameRate = 0.0

var name: String?

}

let someVideoMode = VideoMode()

//Swift 允许直接设置结构体属性的子属性

someVideoMode.resolution.width = 12880

println(someVideoMode.resolution.width)

//类是引用类型，引用的是已存在的实例本身而不是其拷贝。

let hd = Resolution(width: 1920,height: 1080)

let tenEighty = VideoMode()

tenEighty.resolution = hd

tenEighty.interlaced = true

tenEighty.name = "1080i"

tenEighty.frameRate = 25.0

let alsoTenEighty = tenEighty

alsoTenEighty.frameRate = 30.0

if tenEighty === alsoTenEighty {

println("tenEighty 与 alsoTenEighty 是等价的")

}