Finding out RSS Feed URL

I am right now working on RSS feed reader on iPad. But I am stuck at the point how to find out the RSS feed URL of a site through program?

I want the functionality of the thing called "Subscribe".

How exactly is the sites RSS feed 开发者_如何转开发URL found? How do I subscribe the RSS Feed?

You need to look for a <link> item in the HTML head. Thats the standard way of publishing RSS / ATOM feeds. Something like this:

<link rel="alternate" type="application/rss+xml" title="RSS 2.0" 
    href="http://fqdn.com/blog/feed" />