Why doesn't autoload work in yii?

Question

Yii

components/Myclass.php:

namespace yii\components;
class Myclass
{
}

models/Site/user.php:

use yii\components\Myclass;
$ob = new Myclass();

As a result
Class 'yii\components\Myclass' not found

Answer 1

namespace app\components;
class Myclass
{
}

use app\components\Myclass;
$ob = new Myclass();