title: Swift - Expected expression after operator (error)
body: <p>I have 2 errors in the below code, with the same reason why. How do I fix this?</p>
  
  <p>The error says "Expected expression after operator" on both lines <code>return viewControllerAtIndex(index)</code> in the last two functions.</p>
  
  <pre><code>func viewControllerAtIndex(index: Int) -&gt; WalkthroughContentViewController? {
  
      if index == NSNotFound || index &lt; 0 || index &gt;= pageHeadings.count {
          return nil
      }
  
      // Creating a new view controller and passing the data
      if let pageContentViewController = storyboard?.instantiateViewControllerWithIdentifier("WalkthroughContentViewController") as? WalkthroughContentViewController {
  
          pageContentViewController.imageFile = pageImages[index]
          pageContentViewController.heading = pageHeadings[index]
          pageContentViewController.content = pageContent[index]
          pageContentViewController.index = index
  
          return pageContentViewController
      }
  
      return nil
  }
  
  
  func pageViewController(pageViewController: UIPageViewController, viewControllerAfterViewController viewController: UIViewController) -&gt; UIViewController? {
  
      var index = (viewController as! WalkthroughContentViewController).index
      index ++
  
      return viewControllerAtIndex(index)
  }
  
  func pageViewController(pageViewController: UIPageViewController, viewControllerBeforeViewController viewController: UIViewController) -&gt; UIViewController? {
  
      var index = (viewController as! WalkthroughContentViewController).index
      index --
  
      return viewControllerAtIndex(index)
  }
  </code></pre>
  
  <p>This is from Simon Ng's Swift Book.</p>