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copied!<p>This is a classic problem with headers importing headers. You have a circle here: Tile.h is importing Board.h, which imports Tile.h. This confuses the compiler -- it gets stuck in a loop.</p> <p>You solve this by not importing headers into headers. You still need to let the compiler know about <code>Tile</code>, however. In Board.h, make a <a href="http://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/ObjectiveC/Chapters/ocDefiningClasses.html#//apple_ref/doc/uid/TP30001163-CH12-TPXREF124" rel="noreferrer">"forward declaration"</a> of the class:</p> <pre><code>#import <Foundation/Foundation.h> #import "cocos2d.h" @class Tile; // Dear compiler, // Tile is a class that I will need to refer // to in this file. Please consider it to be a // type; I promise it'll be defined at runtime. // Sincerely, stephenalexbrowne @interface Board : NSObject //etc. </code></pre> <p>This assures the compiler that there is a class called <code>Tile</code> that will exist at runtime; you can then refer to that name in the remainder of your header. In your implementation for <code>Board</code>, you import Tile.h. That will let the compiler see the methods and properties associated with the <code>Tile</code> class where they are needed. </p> <p>Likewise, move the <code>#import "Board.h"</code> into Tile.m. Since you aren't referring to the <code>Board</code> class in Tile.h, you don't need to make a forward declaration.</p> <p>In general, it is best to import your class headers only into the implementation files where they are needed. Framework headers, since they will never cause a cycle with your code, can and -- because you need to refer to many of the classes declared in them -- should be imported into your headers.</p>

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