<?php
class DataBase
{
    private $host = 'localhost';
    private $user = 'root';
    private $password = '';

    public function __construct()
    {
        return $this->showDataBaseConnect();
    }

    private function showDataBaseConnect()
    {
        $connect = $this->dataBaseConnect();
        if ($connect){
            return print 'Подключение выполнено!';
        }
        else{
            return print 'Ошибка подключения';
        }
    }

    private function dataBaseConnect()
    {
        return mysqli_connect($this->host, $this->user, $this->password);
    }
}

$connect = new DataBase();
?>