How do I subtract 1 from a label "26" everytime a button is pressed? (Swift Beginner)

Question

Swift Beginner

I want to subtract 1 from a label with value "26" every time the "deal" button is pressed. Do I convert it to an Int? And how do I add calculations to it?

I coded cardsAmount.text = "25", which works. But it needs to subtract 1 every time the button is pressed and not assign a hardcoded value.

Also, in the future I would like to add to the number.

Thanks!

class ViewController: UIViewController {

    @IBOutlet weak var leftPile: UIImageView!

    @IBOutlet weak var rightPile: UIImageView!

    @IBOutlet weak var cardsAmount: UILabel!

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        }


    @IBAction func deal(_ sender: Any) {

        let shuffled = (2...53).shuffled()
        let leftNumber = shuffled[0]
        let rightNumber = shuffled[1]

        //cardsAmount.text = "25"

        leftPile.image = UIImage(named: "c\(leftNumber)")

        rightPile.image = UIImage(named: "c\(rightNumber)")


    }
    .
    .
    .
}

Answer 1

I think you should add a variable as you are a beginner. Use this:

var initialNumber: Int = 1
var number: Int = 26

@IBAction func deal(_ sender: Any) {

    let shuffled = (2...53).shuffled()
    let leftNumber = shuffled[0]
    let rightNumber = shuffled[1]

    number = number - initialNumber
    cardsAmount.text = "\(number)" //This is to subtract. Now you can check if it is a negative number and perform operations ahead using if else

    leftPile.image = UIImage(named: "c\(leftNumber)")

    rightPile.image = UIImage(named: "c\(rightNumber)")


}

You can follow the same approach to add a number. If you want to save the initialNumber then you can write initialNumber = initialNumber + 1 and then use it. Do let me know if you have any query regarding this answer.

Answer 2

You can use property observer.

var number: Int = 26 {
    didSet {
        if number > 0 {
        self.cardsAmount.text = "\(number)"
        }
    }
}

@IBAction func deal(_ sender: Any) {
    let shuffled = (2...53).shuffled()
    let leftNumber = shuffled[0]
    let rightNumber = shuffled[1]

    number -= 1 // whenever number value changes, didSet (property observer) will be called

    leftPile.image = UIImage(named: "c\(leftNumber)")
    rightPile.image = UIImage(named: "c\(rightNumber)")
}