want to create a url like http://www.example.com/uername

[eluser]weblyan[/eluser]
routes.php is a settings file and should not contain any code other than assigning variabels.
Besides, if you write code like that then you are not using the framework correctly.
http://ellislab.com/codeigniter/user-gui...sults.html

Anyway, for the routing, I haven't really tried it but there is a way to set a default controller in the index.php

Code:

/*
* --------------------------------------------------------------------
* DEFAULT CONTROLLER
* --------------------------------------------------------------------
*

Then you can probably use $this->uri->segment(1); the get the username.