title: Directed graph implementation
body: <p>I need to implement a digraph(Directed graph) in c++ as part of a homework and I'm having some issues with how to represent the vertices and edges data types.<br>
  Can anybody please point me to a example or a simple c++ class that implements this so I can study it and extend from there?  </p>
  
  <p>I've googled for a bit but I only found results about using Boost or other libraries, I just need something simple that doesn't rely on any library.   </p>
  
  <p>Thank you.</p>