title: Adding elements to a NSArray
body: <p>I know we could just use a <code>NSMutableArray</code> for the object, but what if that's not an option and we need to add new elements to an <code>NSArray</code>. How would we go about doing this? </p>
  
  <p>My immediate answer would be to create a <code>NSMutableArray</code> with the original <code>NSArray</code>, add the new elements to it, then cast the <code>NSMutableArray</code> back to the original <code>NSArray</code>.</p>
  
  <p>I was asked this in an interview and am curious what a correct solution might be, besides just use a <code>NSMutableArray</code> in the first place.</p>