title: suggestions on how i can resolve this "Semantic Issue" error
body: <p>i have been trying to implement iAD into one of my view controllers and after writing the code for both the .h and .m file.... i get this semantic issue error:</p>
  
  <pre><code>@synthesize of 'weak' property is only allowed in ARC or GC mode
  </code></pre>
  
  <p>i specifically get this error right next to the @implementation of the .m file. any suggestions on how i can resolve this are much appreciated.</p>
  
  <p><strong>ALSO</strong> i was wondering whether it is ok to copy and paste this adbanner(Once its working) from this viewcontroller onto other view controllers withot re-coding ?</p>
  
  <p><strong>This is my code for iAD within the .h file</strong></p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import &lt;iAd/iAd.h&gt;
  
  @interface ViewController : UIViewController &lt;ADBannerViewDelegate&gt;
  @property (weak, nonatomic) IBOutlet ADBannerView *banner;
  
  @end
  </code></pre>
  
  <p><strong>This is my code for iAD within the .m file</strong></p>
  
  <pre><code>#import "ViewController.h"
  
  @interface ViewController ()
  
  @end
  
  @implementation ViewController
  
  - (void)viewDidLoad
  {
  [super viewDidLoad];
  self.banner.delegate = self;
  }
  
  - (void) viewDidLayoutSubviews {
  if (self.banner.bannerLoaded) {
      CGRect contentFrame = self.view.bounds;
      CGRect bannerFrame = self.banner.frame;
      contentFrame.size.height -= self.banner.frame.size.height;
      bannerFrame.origin.y = contentFrame.size.height;
      self.banner.frame = bannerFrame;
  }
  }
  
  - (void)didReceiveMemoryWarning
  {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }
  
  - (BOOL)bannerViewActionShouldBegin:(ADBannerView *)banner willLeaveApplication:    (BOOL)willLeave
  {
  NSLog(@"bannerViewActionShouldBegin");
  return YES;
  }
  
  - (void)bannerViewDidLoadAd:(ADBannerView *)banner
  {
  NSLog(@"bannerViewDidLoadAd");
  }
  
  - (void)bannerView:(ADBannerView *)banner didFailToReceiveAdWithError:(NSError *)error
  {
  NSLog(@"didFailToReceiveAdWithError");
  }
  
  - (void)bannerViewActionDidFinish:(ADBannerView *)banner {
  NSLog(@"bannerViewActionDidFinish");
  }
  
  @end
  </code></pre>