title: Difference between NSString *const and const NSString *?
body: <p>Can someone tell me the difference between the following 2 declarations of NSString? </p>
  
  <pre><code>NSString *const userName = @"ABC"; 
  </code></pre>
  
  <p>and</p>
  
  <pre><code>const NSString *userName = @"ABC"; 
  </code></pre>