How to create the controller for http://localhost in Codeigniter?

I am using codeigniter and was hondering how to create the home page controlller, the controller for http://localhost. As of now i can access all controllers that are http://localhost/{controller}, but not just localhost. My .htaccess is as follows:

RewriteEngi开发者_JAVA百科ne on
RewriteCond $1 !^(index\.php|images|css|sandbox|scripts|robots\.txt)
RewriteRule ^(.*)$ /index.php/test/$1 [L]

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Set the default_controller to the name of the controller you want to use in routes.php