Explain routing in CodeIgniter?

In Software engineering routing is the process of taking a URI endpoint (that part of the URI which comes after the base URL) and decomposing it into parameters to determine which module, controller, and action of that controller should receive the request.In Codeigniter typically there is a one-to-one relationship between a URL string and its corresponding controller class/method.The segments in a URI normally follow this pattern:example.com/class/function/id/.In CodeIgniter, all routing rules are defined in your application/config/routes.php file.