</a><span class="lineno">   20</span>    </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno"><a class="line" href="classtram_1_1_graph.html">   21</a></span><span class="keyword">class </span><a class="code hl_class" href="classtram_1_1_graph.html">Graph</a> {</div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="keyword">protected</span>:</div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno"><a class="line" 