class Person { let name: String // Class initializer init(name: String) { self.name = name } // Using deinit to perform object's resources cleanup deinit { print("Perform the deinitialization") } var numberOfLaughs: Int = 0 func laugh() { numberOfLaughs += 1 // Define a computed property var isHappy: Bool { return numberOfLaughs > 0 } } let david = Person(name: "David") david.laugh() let happy = david.isHappy