title: Header file not being included
body: <p>I'm currently working on a school project with a small group of people and have hit a brick wall regarding #include.  So, the program we're making is a text based RPG style fight simulator.  We have the files:
  source.cpp, menu.h, monster.h, player.h, and item.h.  The problem is that monster.h is not detecting class player despite having #include "player.h".  In fact, it wont import menu.h either (although it doesn't need to), but doesn't have trouble importing item.h.  We have shown our code to the professor as well and he couldn't figure it out either. The code listed below is how we have our header files formatted, please let me know if I'm doing anything wrong. Thank you</p>
  
  <h1>Monster.h</h1>
  
  <pre><code>#pragma once
  #include &lt;iostream&gt;
  #include &lt;string&gt;
  #include &lt;ctime&gt;
  #include "menu.h"
  #include "player.h"
  #include "Item.h"
  using namespace std;
  class Monster {}
  </code></pre>
  
  <h1>player.h</h1>
  
  <pre><code>#pragma once
  #include &lt;iostream&gt;
  #include &lt;string&gt;
  #include "Item.h"
  #include "menu.h"
  using namespace std;
  class Monster;
  class Player : public Monster {}
  </code></pre>