  graph_traits&lt;Graph&gt;::edge_iterator ei, ei_end;
    for (boost::tie(ei, ei_end) = edges(g); ei != ei_end; ++ei)
        std::cout &lt;&lt; &quot;(&quot; &lt;&lt; index[source(*ei, g)] 
                  &lt;&lt; &quot;,&quot; &lt;&lt; index[target(*ei, g)] &lt;&lt; &quot;) &quot;;
    std::cout &lt;&lt; std::endl;
    // ...
    return 0;
  }
</pre>
The output is:
<pre>
  edges(g) = (0,1) (0,3) (2,0) (3,2) (2,4) (1,3) (3,4)
</pre>
<p>&nbsp;
<h2>The Adjacency Structure</h2>
<p>In the next few examples