 we will explore the adjacency structure of the graph
from the point of view of a particular vertex. We will look at the vertices'
in-edges, out-edges, and its adjacent vertices. We will encapsulate this in an
&quot;exercise vertex&quot; function, and apply it to each vertex in the graph.
To demonstrate the STL-interoperability of BGL, we will use the STL <tt>for_each()</tt>
function to iterate through the vertices and apply the function.
<p>&nbsp;
<pre>
  //...
  int main(int,char*[])
  {
    //...
    std