how to use pdo object created in a namespace - php

Question

I am trying to create a PDO object in a class and then use it in another file. The PDO Object gets created (as far as I understand) but I can not use it in the other file and I view these outputs:
PDO Object ( )
connection successful.
Fatal error: Uncaught Error: Call to undefined method
app\db\Connect::query() in /var/www/html/pdoTest/index.php:25 Stack
trace: #0 {main} thrown in /var/www/html/pdoTest/index.php on line 25
My code is as following:
index.php
<?php
ini_set('display_errors', '1');
require_once './vendor/autoload.php';
$con = new \app\db\Connect();
if (!$con)
{
echo 'no PDO object available.';
}else{
echo 'connection successful.' . '<br>';
}
connect.php
<?php
namespace app\db;
use PDO;
class Connect
{
public function __construct()
{
// set the connection variables
$host = 'localhost';
$dbname = 'pdoposts';
$username = 'root';
$password = 'root';
// create the DSN
$dsn = 'mysql:host=' . $host . ';dbname=' .$dbname;
// create PDO connection
try {
$con = new PDO($dsn, $username, $password);
print_r($con);
echo '<br>';
} catch(Exception $e) {
echo $e->getMessage();
}
return $con;
}
}
I have searched all over stackoverflow and other parts of internet but as it seems I am out of luck understanding what my problem is in using the created PDO object. Would you please help me understand it?