title: NSMutableArray vs NSArray which is better
body: <p>This is a bit of a silly question, but if I want to add an object to an array I can do it with both <code>NSMutableArray</code> and <code>NSArray</code>, which should I use?</p>
  
  <pre><code>NSMutableArray * array1;
  [array1 addObject:obj];
  NSArray * array2;
  array2 = [array2 arrayByAddingObject:obj];
  </code></pre>