How to definite (Add) pages in Codeigniter?

Definite (Add) pages in Codeigniter

 //$route['page_name'] = 'controller_name/controller_function';

//D:\wamp\www\codelearning\application\config

 $route['dashboard'] = 'welcome/dashboard';

$route['update'] = 'welcome/update_user';

$route['ajax'] = 'welcome/ajax';

$route['upload'] = 'welcome/file_upload';

$route['register'] = 'welcome/register_form';

$route['update/(:any)'] = 'welcome/update_user';