Trying to pass Doubles from a view to an another but it doesn't work - swift

Question

Hey I'm a newbie to Swift and Xcode and I am trying to make a little app but I have an error and can't fix it.
I'm trying to passe a double from a view to another but it says
Binary operator '+=' cannot be applied to operands of type 'String' and "int"
That's my first view :
#IBOutlet weak var Rned: UILabel!
var ArgentC: Double = 0
override func viewDidLoad() {
super.viewDidLoad()
Rned.text = String(ArgentC)
Rned.backgroundColor = UIColor(patternImage: UIImage(named: "Rectangle2")!)
}
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let SecondViewController = segue.destination as! SacocheVCp2
SecondViewController.ArgentCV = Rned.text!
}
#IBAction func Reset(_ sender: Any) {
Rned.text = String(0)
ArgentC = 0
}
#IBAction func CashButton(_ sender: Any) {
performSegue(withIdentifier: "segueSac", sender: self)
}
and that is my second view with the error, and the error appears when I want to add numbers to my doubles.
#IBOutlet weak var Rend2Label: UILabel!
var ArgentCV = String()
override func viewDidLoad() {
super.viewDidLoad()
Rend2Label.backgroundColor = UIColor(patternImage: UIImage(named: "Label")!)
Rend2Label.text = ArgentCV
// Do any additional setup after loading the view.
}
#IBAction func CinqEur(_ sender: Any) {
ArgentCV += 5 // <== Here
Rend2Label.text = ArgentCV
}
#IBAction func DixEur(_ sender: Any) {
ArgentCV += 10 // <== Here
}
#IBAction func VingtEur(_ sender: Any) {
ArgentCV += 20 // <== Here
}
#IBAction func CinquanteEur(_ sender: Any) {
ArgentCV += 50 // <== Here
}
Thanks for your time.

Answer 1

You don't have to send it as a String , you can send it as Int
secondViewController.argentCV = Int(rned.text) ?? 0 // ?? to avoid crashes but make sure it doesn't destroy logic
Then inside SacocheVCp2
var argentCV = 0 // 0 is default
Finally
argentCV += 5 // <== Here
rend2Label.text = "\(argentCV)"