Cannot use variables inside class [duplicate] - ios

Question

This question already has answers here:
How to initialize properties that depend on each other
(4 answers)
Closed 3 years ago.
I'm trying to follow along CS 193P course and I'm currently on a Lecture 2. The lector made var game = Concentration(numberOfPairsOfCards: cardButtons.count / 2) and it worked fine for him, however, it doesn't work at all for me. Am I missing something? I can't pass anything there.
Here's my ViewController class:
class ViewController: UIViewController {
#IBOutlet weak var flipCountLabel: UILabel!
#IBOutlet var cardButtons: [UIButton]!
var game = Concentration(numberOfPairsOfCards: cardButtons.count / 2)
var emojiChoices = ["🎃", "👻", "🎃", "👻"]
var flipCount = 0 {
didSet {
flipCountLabel.text = "Flips: \(flipCount)"
}
}
//MARK: - IBActions
#IBAction func touchCard(_ sender: UIButton) {
flipCount += 1
if let cardNumber = cardButtons.index(of: sender) {
flipCard(withEmoji: emojiChoices[cardNumber], on: sender)
}
}
//MARK: - Methods
func flipCard(withEmoji emoji: String, on button: UIButton) {
if button.currentTitle == emoji {
button.setTitle("", for: .normal)
button.backgroundColor = #colorLiteral(red: 0.9372549057, green: 0.3490196168, blue: 0.1921568662, alpha: 1)
} else {
button.setTitle(emoji, for: .normal)
button.backgroundColor = #colorLiteral(red: 1, green: 1, blue: 1, alpha: 1)
}
}
}
And Concentration:
class Concentration {
var cards = [Card]()
func chooseCard(at index: Int) {
}
init(numberOfPairsOfCards: Int) {
for _ in 1...numberOfPairsOfCards {
let card = Card()
cards += [card, card]
}
//TODO: - Shuffle the cards
}
}
The error is
Cannot use instance member 'cardButtons' within property initializer;
property initializers run before 'self' is available
and auto completion doesn't work either

Answer 1

You need to make it a var
var game:Concentration!
then inside viewDidLoad
game = Concentration(numberOfPairsOfCards: cardButtons.count / 2)
OR make it a lazy var
lazy var game:Concentration = {
return Concentration(numberOfPairsOfCards:self.cardButtons.count / 2)
}()