title: navigation not working in objective c
body: <p>i created an iPad application, in which navigation is not working,
  for example on click of cell of tableView, it should navigate to new view.</p>
  
  <p>code snippet for the same:</p>
  
  <p><strong>appDelegate.m</strong> </p>
  
  <pre><code>-(void)applicationDidFinishLaunching:(UIApplication *)application {    
  
  UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:viewController];   
  [window addSubview:navController.view];
  [window addSubview:viewController.view];
  [window makeKeyAndVisible];
  }
  </code></pre>
  
  <p>After this i am creating UIViewControllerSubclass, <strong>crollnext</strong>.</p>
  
  <p>Inside this  file i am performing some operation,and finally in my <strong>mainViewController</strong></p>
  
  <pre><code>-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
  
      crollnext *crollController =[[crollnext alloc]initWithNibName:@"crollView" bundle:nil];
  
      [self.navigationController pushViewController:crollController animated:YES];
      [crollController changeProductText:[tableData objectAtIndex:indexPath.row]];
  }
  }
  </code></pre>
  
  <p>Have i made any mistake in code ?</p>
  
  <p>here is a screenshot </p>
  
  <p><img src="https://i.imgur.com/8aL6u.png" alt="screen">
   <strong>Thanks In Advance</strong></p>