Failing to assign values to array from a loop - php

Question

I have got this code:
function retrieve_answers($array = array(), $id = null)
{
include(root_path . '\config.php');
if($id == null)
{
$id = $this->question_id;
}
$query = mysqli_query($link, "SELECT * FROM `answers` WHERE `question_id`='$id'");
if(!mysqli_num_rows($query))
{
throw new Exception('Question not found.');
}
/* - Retrieves the answer rows
- Loops through the array
- Indexes the array and assigns the answerID to the index */
else
{
while($result = mysqli_fetch_array($query))
{
for($i=0;$i<mysqli_num_rows($query);$i++)
{
$array[$i] = $result["id"];
}
}
}
}
Which is a part of a class.
What am I trying to do?
I am trying to accept an array as a parameter, and assign values to the array, the values are to be answerIDs which are linked to the question.
The test.php file is here:
<?php
define('root_path', realpath(dirname(__FILE__)));
include(root_path . '\config.php');
require_once(root_path . '\includes\question.class.php');
$q = new Question(3);
$array = array();
$q->retrieve_answers($array);
var_dump($array);
?>
What happens?
When I try to debug by dumping the array, it shows that the array contains nothing:
array(0) { }
I tried to execute the MySQL result through the class to debug, and it does succeed to retrieve the answer IDs, so I'm pretty positive the issue is in the array.
I would happy to get assistance, thanks in advance.

Answer 1

return value in a function like this
function retrieve_answers($array = array(), $id = null)
{
include(root_path . '\config.php');
if($id == null)
{
$id = $this->question_id;
}
$query = mysqli_query($link, "SELECT * FROM `answers` WHERE `question_id`='$id'");
if(!mysqli_num_rows($query))
{
throw new Exception('Question not found.');
}
/* - Retrieves the answer rows
- Loops through the array
- Indexes the array and assigns the answerID to the index */
else
{
$i = 0;
while($result = mysqli_fetch_array($query))
{
$array[$i] = $result["id"];
$i++;
}
return $array;
}
}
and then get it as
$arr = $q->retrieve_answers($array);
var_dump($arr);