Day 12 commit

day-10.playground/Contents.swift

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+import Cocoa
+
+struct Album {
+    let title: String
+    let artist: String
+    let year: Int
+
+    func printSummary() {
+        print("\(title) (\(year)) by \(artist)")
+    }
+}
+
+let red = Album(title: "Red", artist: "Taylor Swift", year: 2012)
+let wings = Album(title: "Wings", artist: "BTS", year: 2016)
+
+print(red.title)
+print(wings.artist)
+
+red.printSummary()
+wings.printSummary()
+
+
+struct Game {
+    var score = 0 {
+        didSet {
+            print("Score is now \(score)")
+        }
+    }
+}
+
+var game = Game()
+game.score += 10
+game.score -= 3
+game.score += 1
+
+
+struct App {
+    var contacts = [String]() {
+        willSet {
+            print("Current value is: \(contacts)")
+            print("New value will be: \(newValue)")
+        }
+
+        didSet {
+            print("There are now \(contacts.count) contacts.")
+            print("Old value was \(oldValue)")
+        }
+    }
+}
+
+var app = App()
+app.contacts.append("Adrian E")
+app.contacts.append("Allen W")
+app.contacts.append("Ish S")

day-10.playground/contents.xcplayground

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+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<playground version='5.0' target-platform='macos' buildActiveScheme='true' importAppTypes='true'>
+    <timeline fileName='timeline.xctimeline'/>
+</playground>