(Solved) how to load/call a function within a class?

[eluser]Unknown[/eluser]
In order to load a function in a controller from a model is easy but how do you call a function within a class in a controller?

class Crud extends controller {

function index () {

????? how to load a function get_all ?????

}

function get_all () {

$mydata = $this->db->get('users');
foreach ($mydata->result() as $row) {
$aa= $row->username;
echo $aa;
}
}

}