Variable between php files - php

Question

Before anyone points out my code is flawed in security or etc know that I am quite a PHP noob and wouldn't mind you forwarding some help to fix that rather than just yelling it is terrible.
Also I did try this below and it won't work for me because it stores it into the session (Unless session is more secure than I thought. I assume users can extract data from one, correct?):
http://tinyurl.com/myqx3xo
As for my question, how would I be able to access the variable $connectdb in my users function? When I do that it gives me 'Undefined variable' error, and isn't detecting that it exists whatsoever. Both are requires in main\folder\start.php that is loaded every page, and on those pages I attempted to call the function and it gave me a failure. The code works fine when I attempt to hardcode the $connectdb's varible into the functions but again there are good reasons not to. Will add additional details if required.
Undefined variable: connectdb in main\folder\folder1\users.php on the line that starts with $data
main\folder\folder1\users.php function:
function user_data($id) {
$data = array();
$user_id = (int)$id;
$func_num_args = func_num_args();
$func_get_args = func_get_args();
if ($func_num_args > 1) {
unset($func_get_args[0]);
$fields = '' . implode(', ', $func_get_args) . '';
$data = mysqli_fetch_assoc(mysqli_query($connectdb,"SELECT $fields FROM users WHERE id = $id"));
return $data;
}
}
main\folder\folder2\connect.php:
<?php
$connect_fail = 'Example connection failure.';
$dbhost = 'host';
$dbuser = 'user';
$dbpass = 'pass';
$db = 'database';
$connectdb = mysqli_connect($dbhost, $dbuser, $dbpass, $db) or die($connect_fail);
?>

Answer 1

include your connect.php into your user.php
include('../fodler2/connect.php');
function user_data($id) {
$data = array();
$user_id = (int)$id;
$func_num_args = func_num_args();
$func_get_args = func_get_args();
if ($func_num_args > 1) {
unset($func_get_args[0]);
$fields = '' . implode(', ', $func_get_args) . '';
$data = mysqli_fetch_assoc(mysqli_query($connectdb,"SELECT $fields FROM users WHERE id = $id"));
return $data;
}
}

Answer 2

in your users.php file you need to add
include "../folder2/connect.php";