title: How to find which line error occurs in Xcode?
body: <p>I get an error "fatal error: unexpectedly found nil while unwrapping an Optional value" while running my app and I do not know where in the app the error has occurred. </p>
  
  <p>I have two view controllers, and the error for sure doesn't occur in the first view controller because the view of the second controller appears and I also tested with break points in view will appear in the second view controller and everything works fine. </p>
  
  <p>But now I do not know where to put breakpoints in the second view controller. Up to <strong>viewDidLoad</strong> and <strong>viewWillAppear</strong> everything works fine, but at the <strong>didRecievememoryWarning</strong> method the error comes back up again.</p>
  
  <p>Do I have to place break points all over the file and find out which line is causing the error, or is there a quicker way to find out which is the exact line that is causing the error. </p>