php - Error in using PHPSpreadsheet: uncaught error

one text

I have this code to send data for excel printing but I encounter this error:

PHP Fatal error: Uncaught Error: Class "vendor\PhpOffice\PhpSpreadsheet\IOFactory" not found in C:\xampp\htdocs\helloworld.php:10 Stack trace: #0 {main} thrown in C:\xampp\htdocs\helloworld.php on line 10

<?php
// (A) LOAD & USE PHPSPREADSHEET LIBRARY
require __DIR__.'/vendor/autoload.php';
use vendor\PhpOffice\PhpSpreadsheet\Spreadsheet;
use vendor\PhpOffice\PhpSpreadsheet\Reader\Xlsx;
use vendor\PhpOffice\PhpSpreadsheet\Writer;


$file_name = 'excelfile.xlsx';
$spreadsheet = vendor\PhpOffice\PhpSpreadsheet\IOFactory::load($file_name);

how can I resolve this error? Thanks.