import UIKit
import CoreGraphics


struct Circle {
    // 存储属性
    var radius: Double
    // 计算属性
    var diameter: Double {
        set(newDiameter) {
            radius = newDiameter / 2
        }
        get {
            radius * 2
        }
    }
}

var circle = Circle(radius: 5)
print(circle.radius)
print(circle.diameter)

struct Point {
  var x: Int
  var y: Int
  // 初始化器设置初始值
  init() {
    x = 10
    y = 20
  }
}

var p = Point()


struct Point3D {
  var x: Int
  var y: Int
  var z: Int
}

var p3d = Point3D(x: 10, y: 20, z: 30)

struct PointA {
  var x: Int = 10
  var y: Int = 20
}

var pa = PointA()

class Car {
    init() {
        print("Car init!")
    }
    
    func run() {
        print("Car is running!")
    }
}

class Person {
    lazy var car = Car()
    init() {
        print("Person init!")
    }
    
    func goOut() {
        car.run()
    }
}

let ps = Person()
print("-----------")
ps.goOut()

struct PointB {
    var x = 0
    var y = 0
    lazy var z = 0
}
let pb = PointB()
//print(pb.z)



struct CircleA {
    var radius: Double {
        willSet {
            print("willSet", newValue)
        }
        didSet {
            print("didSet", oldValue, radius)
        }
    }
    init() {
        self.radius = 10
        print("Circle init!")
    }
}

var circleA = CircleA()
circleA.radius = 10.5
print(circleA.radius)

struct Shape {
    var width: Int
    var side: Int {
        willSet {
            print("willSetSide", newValue)
        }
        didSet {
            print("didSetSide", oldValue, side)
        }
    }
    var girth: Int {
        set {
            width = newValue / side
            print("setGirth", newValue)
        }
        get {
            print("getGirth")
            return width * side
        }
    }
    func show() {
        print("width=\(width), side=\(side), girth=\(girth)")
    }
}

func test(_ num: inout Int) {
    num = 20
}
var s = Shape(width: 10, side: 4)
test(&s.width)
s.show()
print("----------")
test(&s.side)
s.show()
print("----------")
test(&s.girth)
s.show()

struct CarA {
    static var count: Int = 0
    init() {
        CarA.count += 1
    }
}

let c1 = CarA()
let c2 = CarA()
let c3 = CarA()

print(CarA.count)


// 单例模式
public class FileManager {
    // 延迟初始化
    public static let shared = FileManager()
    // 禁止外部初始化
    private init() {}
    // 方法
    func run() {
        
    }
}

FileManager.shared.run()