内存

class Person {
    var name:String

    init(name:String) {
        self.name = name
    }
     //析构函数 
    deinit{
        print("内存已经释放")
    }
}

引用计数为0的时候系统会自动内存释放，
自动释放内存在遇到强引用循环的时候不会起作用。

强引用循环

用 week或者 unowned可破

class Person {
    var name: String 
    var apartement: Apartment?
    
    init(name: String) {
        self.name = name
        print("person has been initialized")
    }

    deinit{
        print("person has been deIInitalized")
    }
}


class Apartment {
    let name: String
    //week 需要 var与可选型 
    week var tenant: Person?
    //unowned 不需要 不能为空！
    unowned let place: String

    init(name: String) {
        self.name = name
        print("apartment has been initialized")
    } 

    deinit {
        print("apartment has been deinitialized") 
    }
}

week

在闭包中使用self可能会产生强引用循环，造成内存泄漏

class SmartAirConditioner {
    var temperature: Int = 26
    var temperatureChange: ((Int) -> () )!
    init() {
        //捕获列表
        temperatureChange = { [unowned self ] newTemperature in 
            if abs(newTemperature - self.temperature) >= 10 {
                print("abc")
            }else {
                self.temperature = newTemperature
            }
        
        }
    }
}