title: C++ header files including each other
body: <p>I have 2 files that are both including the other file and I am getting strange errors.</p>
  
  <pre><code>#ifndef NODE_H
  #define NODE_H
  
  #include "model.h"
  etc....
  #endif
  
  #ifndef MODEL_H
  #define MODEL_H
  
  #include "Node.h"
  etc....
  #endif
  </code></pre>
  
  <p>Here is my example code of what I am doing. Can somebody explain to me why this is not possible or allowed? And what I should do to get passed this problem.</p>