title: Generate graphs and diagrams with Doxygen
body: <p>I need to generate class diagrams or a graph of a C++ project using Doxygen, I installed it on Ubntu 12.04 as follow:</p>
  
  <pre><code> sudo apt-get install doxygen
   sudo apt-get install doxygen-gui
  </code></pre>
  
  <p>now I don't know how to run the gui, or how to generate the graphs from the surce code, the manual doesn't help.</p>