I've just created a Wordpress wordpress plugin which is all structured inside a class known as isimpledesign_feeds_class() so everything works fine and i'm calling a function out of the class using.

<?php 
$isimpledesign = new isimpledesign_feeds_class(); 
$isimpledesign->isimpledesign_feeds(); 
?>

i had been just wondering if their is a concern calling it such as this because from previous plug ins i've always used

<?php 
if (function_exists('isimpledesign_feeds')) { 
    isimpledesign_feeds(); 
}
?>

to call a function within the theme files.

Just wondering if anybody has any suggestions?

Is the right way to call a function from the class in Wordpress?

Thanks

The very first call is much more object oriented the 2nd appears to become a "old-school" version of the identical wordpress plugin. When the first version works there's not a problem!

Usually theme files of Wordpress don't have classes inside it. Therefore it was working.

However in your wordpress plugin you're using Class. So it's difficult to call any purpose of class without needing object of this class or using classname.