As I see in your code, it seems you are following an old documentation/tutorial about OOP in PHP based on PHP4 (OOP wasn't supported but adapted somehow to be used in a simple ways), since PHP5 an official support was added and the notation has been changed from what it was.
Please see this code review here:
<?php
class my_class{
public $my_value = array();
function __construct( $value ) { // the constructor name is __construct instead of the class name
$this->my_value[] = $value;
}
function set_value ($value){
// Error occurred from here as Undefined variable: my_value
$this->my_value = $value; // remove the $ sign
}
}
$a = new my_class ('a');
$a->my_value[] = 'b';
$a->set_value ('c'); // your array variable here will be replaced by a simple string
// $a->my_class('d'); // you can call this if you mean calling the contructor
// at this stage you can't loop on the variable since it have been replaced by a simple string ('c')
foreach ($a->my_value as &$value) { // look for foreach samples to know how to use it well
echo $value;
}
?>
I hope it helps