public function __construct() in php7 -- Way beyond my grasp - php-7

Question

I'm absolutely lost here.. i've read through previous questions and answers but all i do is break the code even more.
This obviously no longer works in php7, so i'm trying (and failing) to get this to work. It's probably a slap-head for most of the folks here, but how do i get this to work in php7? Thanks.
public function __construct() {
$arrConfig = include './config.php';
$this->objDB = mysql_connect($arrConfig['db']['host'], $arrConfig['db']['username'], $arrConfig['db']['password']);
mysql_select_db($arrConfig['db']['dbname'], $this->objDB);
}
results in the following error.
Fatal error: Uncaught Error: Call to undefined function mysql_connect()
cheers.

Answer 1

I hate to say "RFTM", but it's sound advice in this case. If yer having problems with a function, the first thing you should do is read the documentation on it.
Here they are: http://php.net/manual/en/function.mysql-connect.php
In a highlighted box at the top of the page it says this:
Warning
This extension was deprecated in PHP 5.5.0, and it was removed in PHP 7.0.0.
It then goes on to give advice of what to do instead, which is:
Instead, the MySQLi or PDO_MySQL extension should be used. See also MySQL: choosing an API guide and related FAQ for more information. Alternatives to this function include:
mysqli_connect()
PDO::__construct()
Have a read of the docs, they'll steer you in the right direction. Come back and ask further questions if you get stuck on your revised solution.