Swift-类与结构体自测题

<pre name="code" class="python">1.有一个结构体和类，定义如下<pre name="code" class="java">struct Resolution {
    var width = 0
    var heigth = 0
}
class VideoMode {
    var resolution = Resolution()
    var interlaced = false
    var frameRate = 0.0
    var name: String?
}

let hd = Resolution(width: 1920, height: 1080)
var cinema = hd
cinema.width = 2048
println("cinema is now  \(cinema.width) pixels wide")
<pre name="code" class="python">println("hd is now  \(hd.width) pixels wide")

上面当输出语句分别输出什么？

let tenEighty = VideoMode()
tenEighty.resolution = hd
tenEighty.interlaced = true
tenEighty.name = "1080i"
tenEighty.frameRate = 25.0
let alsoTenEighty = tenEighty
alsoTenEighty.frameRate = 30.0

println("The frameRate property of tenEighty is now \(tenEighty.frameRate)")

上面当输出呢？

这就是值类型和引用类型的区别？