Php和Controller：浏览器找不到Base Controller

I'm doing an app and I'm using a base controller to create others ones. When I launch a controller I see that error:

Fatal error: Class 'BaseController' not found in C:\xampp\htdocs\sFitness\api\1-dev\controllers\PeopleController.php on line 3

The problem is that in the same folder I've BaseController.php

following I send you the PeopleController.php:

<?php

class PeopleController extends BaseController {

    public function processGetRequest($request) {
        $result = NULL;
        $result = $this->_model->getAllAthletes();  

        return $result;

    }
}

?>

following the BaseController.php

<?php

abstract class BaseController {

    public $_model;

    public function __construct() {
        $this->_model = new Model();
    }

}
?>

How can I resolve this problem? What's the problem?

Thanks so much

You should import your other file so php can see it; in PeopleController, do the following:

 <?php
require_once "BaseController.php";

class PeopleController extends BaseController 
{

    public function processGetRequest($request) 
    {
         $result = NULL;
         $result = $this->_model->getAllAthletes();  

         return $result;

    }
}

?>