属性、方法以及继承

10 属性 inout.playground/Contents.swift

@@ -1,4 +1,5 @@
 import UIKit
+import CoreGraphics
 
 
 struct Circle {
@@ -100,3 +101,70 @@ struct CircleA {
 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()
+