PHP OOP not passing variables in the class - php

Question

I have a PHP class that is meant to get a mysqli query, make a multidimensional array, and currently just echo the whole array. It is this code:
include("connect.php");
class database
{
public $motto;
public $motto_array = array();
public $rating;
public $rating_array = array();
public $category;
public $score;
private $mysqli;
public $counter_array = array();
public $multi_dim_values = array();
public $multi_dim_category = array();
function setMysqli($mysqli)
{
$this->mysqli = $mysqli;
}
function setCategory($category)
{
$this->category = $category;
}
function query_category()
{
if ($stmt = $this->mysqli->prepare("SELECT motto, score FROM mottos WHERE category=? ORDER BY score DESC"))
{
$stmt->bind_param("s", $this->category);
$stmt->execute();
$stmt->bind_result($motto, $ranking);
while ( $stmt->fetch() ) {
$this->motto_array[] = $motto;
$this->rating_array[] = $ranking;
}
$stmt->close();
}
}
function multi_dim_array()
{
$multi_dim_values = array($this->motto_array, $this->rating_array);
$counter_array = range(0,count($this->motto_array)-1);
foreach($counter_array as $index => $key) {
$foreach_array = array();
foreach($multi_dim_values as $value) {
$foreach_array[] = $value[$index];
}
$multi_dim_category[$key] = $foreach_array;
}
return $multi_dim_category;
}
}
$class = new database;
$class->SetMysqli($mysqli);
$class->SetCategory("person");
$class->query_category();
print_r($class->multi_dim_array);
print_r($class->multi_dim_category);
connect.php has the database connection information for the mysqli.
I am learning OOP, so I did this in procedural, and it works fine, with this code:
include("connect.php");
function category($mysqli, $cat)
{
if ($stmt = $mysqli->prepare("SELECT motto, score FROM mottos WHERE category=? ORDER BY score DESC"))
{
$stmt->bind_param("s", $cat);
$stmt->execute();
while($stmt->fetch())
{
printf ("[%s (%s) in %s] \n", $motto, $ranking, $category);
$array .= compact("motto", "category", "ranking");
}
print_r($array);*/
$a = array();
$b = array();
$c = array();
$stmt->bind_result($motto, $ranking);
while ( $stmt->fetch() ) {
$a[] = $motto;
$b[] = $ranking;
}
$result = array();
$values = array($a, $b);
$c = range(0,count($a)-1);
foreach($c as $index => $key) {
$t = array();
foreach($values as $value) {
$t[] = $value[$index];
}
$result[$key] = $t;
}
return $result;
$stmt->close();
}
}
$cat = "person";
$array_one = category($mysqli, $cat);
print_r($array_one);
This prints the multidimensional array just like I want it to.
What am I doing wrong in the OOP code?
Thank you.

Answer 1

Your code:
print_r($class->multi_dim_array);
You forgot the (), so you're not invoking the method. You're accessing a (non-existent) property. Try this:
print_r($class->multi_dim_array());