title: calculate std::distance between two std::reverse_iterators
body: <p>I have a code snippet like this:</p>
  
  <pre><code>int* array = new int[size];
  std::reverse_iterator&lt;int*&gt; it2 = ... // arbitrary in array
  </code></pre>
  
  <p>How can i compute the distance between last and <code>it2</code>?
  I tried this, but it gives back zero:</p>
  
  <pre><code>std::distance(std::reverse_iterator&lt;int*&gt;(array + size), it2);
  </code></pre>