title: Difference between @interface declaration and @property declaration
body: <p>I'm new to C, new to objective C. For an iPhone subclass, Im declaring variables I want to be visible to all methods in a class into the @interface class definition eg</p>
  
  <pre><code>@interface myclass : UIImageView {
      int aVar;
  }
  </code></pre>
  
  <p>and then I declare it again as</p>
  
  <pre><code>@property int aVar;
  </code></pre>
  
  <p>And then later I </p>
  
  <pre><code>@synthesize aVar;
  </code></pre>
  
  <p>Can you help me understand the purpose of three steps? Am I doing something unnecessary?</p>
  
  <p>Thanks.</p>