Leading zero in calculator swift2

Question

I've got a problem with leading zero in my simple app (Calculator). On start Zero is printed on label, but when I tap button for example "1" I see "01". It doesn't look good, so I would to change it. My code is below. Can somebody help me in it?

import UIKit

class ViewController: UIViewController {

var previousValue:Int?


override func viewDidLoad() {
    super.viewDidLoad()
    // Do any additional setup after loading the view, typicala       nib.
}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

//display
@IBOutlet weak var displayLabel: UILabel!

// buttons
@IBAction func buttonPressed(sender: AnyObject) {

   let numb = (sender as! UIButton).tag

    displayLabel.text = "\(displayLabel.text!)\(numb)"

}
//plus    
@IBAction func plusPress(sender: AnyObject) {
    previousValue = Int(displayLabel.text!)
    displayLabel.text = "+"

}
//minus    
@IBAction func minusPress(sender: AnyObject) {
    previousValue = Int(displayLabel.text!)
    displayLabel.text = "-"
}

// count
@IBAction func count(sender: AnyObject) {
    let result = previousValue! + Int(displayLabel.text!)!
    displayLabel.text = "\(result)"

}


@IBAction func clear(sender: AnyObject) {
    displayLabel.text=""
}

}

Answer 1

Check the contents of displayLabel.text first. If it is 0, then just set displayLabel.text to the number that was pressed. Also, if you declare sender in buttonPressed to be a UIButton, then you don't have to cast it:

@IBAction func buttonPressed(sender: UIButton) {
    let numb = sender.tag

    if displayLabel.text == "0" {
        displayLabel.text = "\(numb)"
    }
    else {
        displayLabel.text = "\(displayLabel.text!)\(numb)"
    }
}