title: When to include the #import in the implementation file
body: <p>Learning Objective-C and other c based Languages I learned that you should put the #includes and the #imports in the header file. And the @class goes there as well. Recently looking at example code from apple and other sources around the web the @class is in the header and all the imports are in the implementation file.</p>
  
  <p>Which is correct? Are there reasons for both? Also why do you need to provide the @class declaration if you are importing the header file.</p>