title: Creating a StopWatch in Iphone
body: <p>I am trying to create a simple stopwatch. I referred to this website ( <a href="http://www.apptite.be/tutorial_ios_stopwatch.php" rel="noreferrer">http://www.apptite.be/tutorial_ios_stopwatch.php</a>) to do this app. When I click the start button, I get -596:-31:-23:-648 and the stopwatch does not run.</p>
  
  <p>The code looks like:</p>
  
  <p>ViewController.h</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  
  @interface ViewController : UIViewController{
      UILabel *lbl;
      NSTimer *stopTimer;
      NSDate *startDate;
  }
  
  @property (strong,nonatomic) IBOutlet UILabel *lbl;
  
  -(IBAction)startPressed:(id)sender;
  -(IBAction)stopPressed:(id)sender;
  
  -(void)updateTimer;
  
  @end
  </code></pre>
  
  <p>ViewController.m</p>
  
  <pre><code>#import "ViewController.h"
  
  @interface ViewController ()
  
  @end
  
  @implementation ViewController
  @synthesize lbl;
  
  - (void)viewDidLoad
  {
      [super viewDidLoad];
      lbl.text = @"00.00.00.000";
  }
  
  - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
  }
  -(IBAction)startPressed:(id)sender{
      if (stopTimer == nil) {
          stopTimer = [NSTimer scheduledTimerWithTimeInterval:1.0/10.0
                                                       target:self
                                                     selector:@selector(updateTimer)
                                                     userInfo:nil
                                                      repeats:YES];
      }
  }
  -(IBAction)stopPressed:(id)sender{
      [stopTimer invalidate];
      stopTimer = nil;
      //[self updateTimer];
  
  }
  -(void)updateTimer{
      NSDate *currentDate = [NSDate date];
      NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate];
      NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval];
      NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
      [dateFormatter setDateFormat:@"HH:mm:ss.SSS"];
      [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]];
      NSString *timeString=[dateFormatter stringFromDate:timerDate];
      lbl.text = timeString;
  }
  
  @end
  </code></pre>
  
  <p>Need some guidance on solving the error. Not sure where the error is. Appreciate any help...</p>