问题
I have searched alot that what is CI_Controller class? Actually, it is a base class and all controllers extend from CI_Controller class in codeigniter? Whether, it is abstract class or not?
回答1:
in your directory structure open system->core->controller.php you will see the class name is CI_Controller
来源：https://stackoverflow.com/questions/43602164/what-is-ci-controller-built-in-class-whether-it-is-abstract-or-not