what are the advantage of using protocols in Objective-C, when we require them?
<p>what are the Advantages of using protocols in Objective-C, when we require them? I have read the objective-C programming guide it shows mainly 3 advantages:</p>

<ol>
<li><p>To declare methods that others are expected to implement.</p></li>
<li><p>To declare the interface to an object while concealing its class</p></li>
<li><p>To capture similarities among classes that are not hierarchically related.</p></li>
</ol>

<p>Can any one explain me (2) and (3), I am not able to get it, as I have read details of them in Obj-C programming Guide? Are there any other advantages of using protocol? How can you describe why we need protocols in Objective-C?</p>
