title: uses undefined class despite using include
body: <p><br>I want to create an Instance of my game class in another class but i get an <code>uses undefined class</code> error although i include <code>game.h</code>.</p>
  
  <p>Game.h</p>
  
  <pre><code>#ifndef GAME_H
  #define GAME_H
  
  #include "Move.h"
  
  class Game
  {
    private:
  
      //--------------------------------------------------------------------------
      // Private copy constructor
      //
      Game(const Game&amp; original);
  
   public:
      //--------------------------------------------------------------------------
      // Public assignment operator
      //
      Game&amp; operator=(const Game&amp; original);
  
      //Constructors
      Game ();
  
      //Destructor
      ~Game ();
  };
  #endif // _GAME_H
  </code></pre>
  
  <p>The Header where i want to create a Game Object:<br><br>
  Move.h</p>
  
  <pre><code>#ifndef MOVE_H
  #define MOVE_H
  
  #include "Game.h"
  
  class Move : public Command
  {
    private:
      Move (const Move&amp; original);
      Move&amp; operator=(const Move&amp; original);
  
      Game m_game_;  //Error
   };
    #endif // _MOVE_H
  </code></pre>
  
  <p>Visual Studios is throwing:</p>
  
  <pre><code>    move.h(40): error C2079: 'Move::m_game_' uses undefined class 'Game'
  </code></pre>
  
  <p>It works if i use <code>Game* game;</code> but that's not what i need/want.</p>
  
  <p>Why does the compiler gives me an error of undefined class? <br>
  Much thanks to any help.</p>