nt</code> &mdash;  The index
   </td>
</tr>
</table>
</div>
<a name="getNextVertexID()"></a>
<table cellspacing="0" cellpadding="0" class="detailHeader">
<tr>
<td class="detailHeaderName">getNextVertexID</td><td class="detailHeaderParens">()</td><td class="detailHeaderType">method</td><td class="detailHeaderRule">&nbsp;</td>
</tr>
</table>
<div class="detailBody">
<code>public function getNextVertexID():int</code><p>
   Returns the next unused vertex id.
      </p><p>this is the next free index in the verex