problem with PHP class function ()

this is my first question here and i hope you can help me ..

I am trying to find a soloution of the towers of hanoi problem by three search ways (BFS-DFS-IDS) so I use "state" class whitch defined by 5 variables as here :

class state {

var $tower1 = array();
var $tower2 = array();
var $tower3 = array();
var $depth;
var $neighbors = array();

and it also has many function one of them is getneighbors() which supposed to fill the array $neighb开发者_高级运维ors with state neighbors and they are from the type "state"

and here is the function :

function getneighbors ()

{

    $temp=$this->copy();

    $neighbor1= $this->copy();

    $neighbor2= $this->copy();

    $neighbor3= $this->copy();

    $neighbor4= $this->copy();

    $neighbor5= $this->copy();

    $neighbor6= $this->copy();

    if(!Empty($temp->tower1))
    {

         if(!Empty($neighbor1->tower2))
         {
            if(end($neighbor1->tower1) < end($neighbor1->tower2))
            {
                array_unshift($neighbor1->tower2,array_pop($neighbor1->tower1));
                array_push($neighbors,$neighbor1);
         }}
         else
             {
         array_unshift($neighbor1->tower2, array_pop($neighbor1->tower1));             
          array_push($neighbors,$neighbor1);
             }



        if(!Empty($neighbor2->tower3))
         {
            if(end($neighbor2->tower1) < end($neighbor2->tower3))
            { array_unshift($neighbor2->tower3, array_pop($neighbor2->tower1));
              array_push($neighbors,$neighbor2);
        }}


        else
            {
         array_unshift($neighbor2->tower3,array_shift($neighbor2->tower1));
         array_push($neighbors,$neighbor2);
            }

        }
               if(!Empty($temp->tower2))
    {


         if(!Empty($neighbor3->tower1))
         {

           if(end($neighbor3->tower2) < end($neighbor3->tower1))
           {   array_unshift($neighbor3->tower1,array_shift($neighbor3->tower2));
               array_push($neighbors,$neighbor3);
         }

         }
             else
             {
         array_unshift($neighbor3->tower1,array_shift($neighbor3->tower2));
         array_push($neighbors,$neighbor3);

         }



        if(!Empty($neighbor4->tower3))
         {
            if(end($neighbor4->tower2) < end($neighbor4->tower3))
            { array_unshift($neighbor4->tower1,array_shift($neighbor4->tower2));
              array_push($neighbors,$neighbor4);
            }
        }
            else{
         array_unshift($neighbor4->tower3,array_shift($neighbor4->tower2));
            array_push($neighbors,$neighbor4);
         }

        }
          if(!Empty($temp->tower3))
    {


         if(!Empty($neighbor5->tower1))
         {
            if(end($neighbor5->tower3) < end($neighbor5->tower1))
            {array_unshift($neighbor5->tower1,array_shift($neighbor5->tower3));
             array_push($neighbors,$neighbor5);
            }
         }
             else{
         array_unshift($neighbor5->tower1,array_shift($neighbor5->tower3));
         array_push($neighbors,$neighbor5);}



        if(!Empty($neighbor6->tower2))
         {
            if(end($neighbor6->tower3) < end($neighbor6->tower2))
            {  array_unshift($neighbor6->tower2,array_shift($neighbor6->tower3));
             array_push($neighbors,$neighbor6);
        }}
            else{
         array_unshift($neighbor6->tower2,array_shift($neighbor6->tower3));
         array_push($neighbors,$neighbor6);}

        }
        return $neighbors;
}

note that toString and equals and copy are defined too

now the problem is that when I call getneighbors() it returns an empty $neighbors array

can you pleas tell me the problem ?

You have a scoping issue. $neighbors is a class variable and not a PHP global. Everywhere you refer to $neighbors change it to $this->neighbors.