title: Declare instance variable nonproperty and property same name
body: <p>Why in many fragment code declare instance variable like and for what? what different about property and non property</p>
  
  <pre><code>#import &lt;Foundation/Foundation.h&gt;
  
  @interface class1:NSObject
  
  {
     NSMutableString *currentData;
  }
  @property (nonatomic, retain) NSMutableString * currentData;
  </code></pre>