PHP Fatal error: Uncaught Error: Class 'Elliptic\EC' not found - php

Question

I want to generate private/public keys using Elliptic Curve Cryptography in PHP.
I have used this library: https://github.com/simplito/elliptic-php
my code:
<?php
use Elliptic\EC;
// Create and initialize EC context
// (better do it once and reuse it)
$ec = new EC('secp256k1');
// Generate keys
$key = $ec->genKeyPair();
$publicKey = $key->getPublic('hex');
$privateKey = $key->getPrivate('hex');
// Print the keys to the console
echo "The address1 is {$publicKey}. \r\n";
echo "The address1 is {$privateKey}. \r\n";
but it shows me this error:
PHP Fatal error: Uncaught Error: Class 'Elliptic\EC' not found in /home/istabraq/bctest/test1/keygenerator.php:6
I have installed composer Composer 1.6.3
from this tutorial:
https://linuxize.com/post/how-to-install-and-use-composer-on-ubuntu-18-04/
then installed sudo apt-get install php7.2-gmp
and installed composer require simplito/elliptic-php and finally installed composer require simplito/bn-php but the last command line shows me this output:
Using version ^1.1 for simplito/bn-php
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Writing lock file
Generating autoload files
what I have missed please help? I search for problem but did not have tutorial.

Answer 1

try include file with class or if exists vendor/autoload.php include it, for example:
<?php
include 'path/vendor/autoload.php'; //or 'path/file/EC.php'
use Elliptic\EC;
// Create and initialize EC context
// (better do it once and reuse it)
$ec = new EC('secp256k1');
// Generate keys
$key = $ec->genKeyPair();
$publicKey = $key->getPublic('hex');
$privateKey = $key->getPrivate('hex');
// Print the keys to the console
echo "The address1 is {$publicKey}. \r\n";
echo "The address1 is {$privateKey}. \r\n";