php - Extending a class with a namespace is saying class not found -

i have structure so:

index.php core   exceptions     exceptioncore.php     exceptionutil.php vendor   autoload stuff 

index file:

<?php  require 'vendor/autoload.php';  new \core\exceptions\exceptioncore\exceptioncore(); 

exceptioncore:

<?php  namespace core\exceptions\exceptioncore;  class exceptioncore {     public function __construct()     {         echo 'fffhf';     } } 

but getting error:

fatal error: uncaught error: class 'core\exceptions\exceptioncore\exceptioncore' not found in c:\xampp\htdocs\user\index.php:5 stack trace: #0 {main} thrown in c:\xampp\htdocs\user\index.php on line 5

the autoloader expects find class core\exceptions\exceptioncore\exceptioncore in file core/exceptions/exceptioncore/exceptioncore.php.

read more psr-0 , prs-4 standards.