ference_type</code></td>

              <td><code>R</code>: <code>reference</code> type</td>
            </tr>

            <tr>
              <td><code>i</code>: object of type <code>T</code> (an
              iterator)</td>

              <td><code>n</code>: object of type <code>D</code> (an
              index)</td>
            </tr>
          </table>
        </td>
      </tr>

      <tr>
        <th>Template</th>

        <th>Supplied Operations</th>

        <th>Requirements</th>
      </tr>

      <t