Swift编程中用以管理内存的自动引用计数详解

class StudDetails {
    var stname: String!
    var mark: Int!
    init(stname: String, mark: Int) {
        self.stname = stname
        self.mark = mark
    }
   
    deinit {
        println("Deinitialized \(self.stname)")
        println("Deinitialized \(self.mark)")
    }
}

let stname = "swift"
let mark = 98

println(stname)
println(mark)

swift
98

class studmarks {
    let name: String
    var stud: student?
   
    init (name: String) {
        println("Initializing: \(name)")
        self.name = name
    }
   
    deinit {
        println("Deallocating: \(self.name)")
    }
}

class student {
    let name: String
    var strname: studmarks?
   
    init (name: String) {
        println("Initializing: \(name)")
        self.name = name
    }
   
    deinit {
        println("Deallocating: \(self.name)")
    }
}

var shiba: studmarks?
var mari: student?

shiba = studmarks(name: "Swift")
mari = student(name: "ARC")

shiba!.stud = mari
mari!.strname = shiba

Initializing: Swift
Initializing: ARC

class module {
    let name: String
    init(name: String) { self.name = name }
    var sub: submodule?
    deinit { println("\(name) Is The Main Module") }
}

class submodule {
    let number: Int
   
    init(number: Int) { self.number = number }
   
    weak var topic: module?
   
    deinit { println("Sub Module with its topic number is \(number)") }
}

var toc: module?
var list: submodule?
toc = module(name: "ARC")
list = submodule(number: 4)
toc!.sub = list
list!.topic = toc

toc = nil
list = nil

ARC Is The Main Module
Sub Module with its topic number is 4

class student {
    let name: String
    var section: marks?
   
    init(name: String) {
        self.name = name
    }
   
    deinit { println("\(name)") }
}
class marks {
    let marks: Int
    unowned let stname: student
   
    init(marks: Int, stname: student) {
        self.marks = marks
        self.stname = stname
    }
   
    deinit { println("Marks Obtained by the student is \(marks)") }
}

var module: student?
module = student(name: "ARC")
module!.section = marks(marks: 98, stname: module!)
module = nil

ARC
Marks Obtained by the student is 98

class HTMLElement {
    let samplename: String
    let text: String?
   
    lazy var asHTML: () -> String = {
        if let text = self.text {
            return "<\(self.samplename)>\(text)</\(self.samplename)>"
        } else {
            return "<\(self.samplename) />"
        }
    }
   
    init(samplename: String, text: String? = nil) {
        self.samplename = samplename
        self.text = text
    }
   
    deinit {
        println("\(samplename) is being deinitialized")
    }
}

var paragraph: HTMLElement? = HTMLElement(samplename: "p", text: "Welcome to Closure SRC")
println(paragraph!.asHTML())

 class HTMLElement {
    let module: String
    let text: String?
   
    lazy var asHTML: () -> String = {
        [unowned self] in
        if let text = self.text {
            return "<\(self.module)>\(text)</\(self.module)>"
        } else {
            return "<\(self.module) />"
        }
    }
   
    init(module: String, text: String? = nil) {
        self.module = module
        self.text = text
    }
   
    deinit {
        println("\(module) the deinit()")
    }
}

var paragraph: HTMLElement? = HTMLElement(module: "Inside", text: "ARC Weak References")
println(paragraph!.asHTML())
paragraph = nil

<Inside>ARC Weak References</Inside>
Inside the deinit()