Sum of UITextfield values crashes when any field is left blank

Question

Hello all. I just recently started trying to learn coding in Swift 2. I am trying to make a very simple app where I can add scores, push my "calculate" button and display the total in a label. I was able to do that as seen in the screenshot. The problem I have is if I don't put a score in one of the textfields and still try to calculate it, it crashes. This is my code:

    class ViewController: UIViewController {


@IBOutlet weak var score1: UITextField!

@IBOutlet weak var score2: UITextField!

@IBOutlet weak var score3: UITextField!

@IBOutlet weak var total: UILabel!

@IBAction func Calculate(sender: AnyObject) {

    let score1 = Int(score1.text!)!
    let score2 = Int(score2.text!)!
    let score3 = Int(score3.text!)!
    let alltogether = (scoreone) + (scoretwo) + (scorethree)

    total.text = "Your total score is \(alltogether)!"

}

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

}

Could someone point me in the direction I need to look. I am thinking I need to add some sort of exemption if the field is nil. Or something along the lines of making the default int 0??? Thank you all!

You're forcibly unwrapping an optional variable. If any field, say text field `score1`, is empty, the the following line of code, `let score1 = Int(score1.text!)!`, will fail as the `Int` initializer will return `nil` when send an empty string. There exists several threads here on SO explaining how to safely unwrap optionals, as well as how to convert `String` values to `Int`, see e.g. [LeoDabus answer in this thread](http://stackoverflow.com/a/34294660/4573247). — dfrib, Jan 13 '16 at 01:11
Possible duplicate of [Swift - Converting String to Int](http://stackoverflow.com/questions/24115141/swift-converting-string-to-int) — dfrib, Jan 13 '16 at 01:20

score 2 · Accepted Answer · answered Jan 13 '16 at 01:17

2

let score1 : Int = Int(score1.text ?? "") ?? 0
let score2 : Int = Int(score2.text ?? "") ?? 0
let score3 : Int = Int(score3.text ?? "") ?? 0

This will yield value 0 in case your fields are empty or otherwise non-numerical (or if UITextField property .text contains nil).

answered Jan 13 '16 at 01:17

dfrib

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Thanks so much! Worked perfect. That answer helped me figure out how to work in Double as well. – CincyWong Jan 13 '16 at 02:30
@ChrisWong Happy to help! Have a look at the linked thread http://stackoverflow.com/questions/24115141/swift-converting-string-to-int as well, lots of valuable information there in this context. – dfrib Jan 13 '16 at 02:31

Sum of UITextfield values crashes when any field is left blank

1 Answers1