Array Object In Php - php

Question

i want to store Student Object to array. and i try to do with below code. but it always show array count as 0
class Student
{
$StudID = 0;
$Name = null;
}
class Students
{
static private $StudentData = array();
static public function AddNewStudent($id,$name)
{
echo("AuctionID :".$AuctionID."<br/>");
try{
$objstd = new Student();
$objstd->StuID = $id;
$objstd->Name = &name;
array_push($StudentData, $objstd);
}
catch (Exception $e)
{
echo("Error".$e->getMessage());
}
}
static public function TotalStudent()
{
return count($StudentData);
}
}
Students::AddNewStudent(1,"name");
Students::AddNewStudent(2,"name2");
Students::AddNewStudent(3,"name3");
echo('Total auction running : '.Students::TotalStudent().'<br/>');
when i try to show array count it shows 0. i want to store all student data in static list
or then after when ever i want to see the list i get the list from static class only...

Answer 1

Because you're creating a new array instead of referencing the one you declared. Use the self keyword to reference your static object property:
class Students
{
static private $StudentData = array();
static public function AddNewStudent($id,$name)
{
echo("AuctionID :".$AuctionID."<br/>");
try{
$objstd = new Student();
$objstd->StuID = $id;
$objstd->Name = &name;
array_push(self::$StudentData, $objstd);
}
catch (Exception $e)
{
echo("Error".$e->getMessage());
}
}
static public function TotalStudent()
{
return count(self::$StudentData);
}
}

Answer 2

In php you have to prefix static variables with self::, like this:
array_push(self::$StudentData, $objstd);
// and in count:
return count(self::$StudentData);

Answer 3

Why that complicated? Your Student class should take care of it's own, same for Students. Example:
$students = new Students();
$students[] = new Student(1, "name");
$students[] = new Student(2, "name2");
$students[] = new Student(3, "name3");
printf('Total auction running : %d.', count($students));
Example output:
Total auction running : 3.
The classes:
class Student
{
/**
* #var int
*/
private $id;
/**
* #var string
*/
private $name;
/**
* #param int $id
* #param string $name
*/
public function __construct($id, $name) {
$this->id = $id;
$this->name = $name;
}
/**
* #return string
*/
public function getName()
{
return $this->name;
}
/**
* #return int
*/
public function getId()
{
return $this->id;
}
}
class Students extends ArrayObject
{
public function __construct()
{
parent::__construct(array());
}
public function offsetSet($index, $newval) {
if (!($newval instanceof Student)) {
throw new InvalidArgumentException('You can only add values of type Student.');
}
parent::offsetSet($index, $newval);
}
}