How to do a CountDown timer using Swift
<p>Hello I am developing a countdown timer,which has to stop after 8 hours. Here it is:</p>

<pre><code>import UIKit

class ViewController: UIViewController {

   var timer = NSTimer()
   var counter = 0

@IBOutlet weak var Label: UILabel!

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

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

@IBAction func Start(sender: AnyObject) {
counter = 28800
Label.text = String(counter)
timer = NSTimer.scheduledTimerWithTimeInterval(1, target: self, selector: Selector("updateTimer"), userInfo: nil, repeats: true)
     }

  func updateTimer () {

counter -= 1
Label.text = String(counter)

 }

 @IBAction func Stop(sender: AnyObject) {

timer.invalidate()
 }
 }
</code></pre>

<p>But in stead of having 28800 seconds (which is 8hours)I want to display 08:00:00 , 07:59:59 , 07:59:58, so on... At the moment it is showing 28800, 28799, 28798, so on. Do you have an idea how to format it as a real clock (08:00:00)?</p>