Re: [PHP-WIN] Static array causing problem in recursion

2009/12/4 Midhun Girish <[email protected]>:
> Hello ,
>
> Richard Quadling thank you so much.. your trick worked... :) now its
> working.. heres the modified code...
>
>  public function getAllChildren($node,$level,$firstCall=false)
>>
>>   {
>>       static $rootsarray=array();
>>       static $levelcount;
>>       if($firstCall) {
>>           $rootsarray=array();
>>       }
>>       $levelcount=$level;
>>       $child=self::getChild($node);
>>       if($child==''||$levelcount==0)
>>       {
>>           return 1;
>>       }
>>       else
>>       {
>>           $levelcount--;
>>           $rootsarray[]=$child;
>>           self::getAllChildren($child,$levelcount,False);
>>       }
>>       return $rootsarray;
>>
>>   }
>>
>
> and i call the function like :
>
>  $nodearray=tree::getAllChildren('W1',10,true);
>
>
> Thank you so much for your support...
>
> Midhun Girish
>
>
> On Fri, Dec 4, 2009 at 3:18 PM, Richard Quadling <[email protected]>
> wrote:
>>
>> 2009/12/4 Midhun Girish <[email protected]>
>> >
>> > Hello guys,
>> > I was trying to use a recursive function to do a tree traversal.. i used
>> > a
>> > static array to store the nodes at each recursion.. The function works
>> > correctly if it is called only once during an execution.. but when i
>> > call it
>> > twice or more, the nodes get appended to the array...hers the var dump
>> > of
>> > the array...
>> > Three:Array ( [0] => W4 )
>> > Two:Array ( [0] => W4 [1] => W3 [2] => W4 )
>> > One:Array ( [0] => W4 [1] => W3 [2] => W4 [3] => W2 [4] => W3 [5] => W4
>> > )
>> >
>> > I tried to reset() the array and all but not working..i am not able to
>> > chnage the index of the $rootsarray  back to 0... the new elelnts are
>> > added
>> > at the end only...can anyone give me a push in the right direction?? Im
>> > using PHP Version 5.2.9 in XAMPP... Hers the source...
>> >
>> >    public function getAllChildren($node,$level)
>> >    {
>> >        static $rootsarray=array();
>> >        static $levelcount;
>> >        $levelcount=$level;
>> >        $child=self::getChild($node);
>> >        if($child==''||$levelcount==0)
>> >        {
>> >            return 1;
>> >        }
>> >        else
>> >        {
>> >            $levelcount--;
>> >            $rootsarray[]=$child;
>> >            self::getAllChildren($child,$levelcount);
>> >        }
>> >        return $rootsarray;
>> >
>> >    }
>> >
>> > Midhun Girish
>>
>> Of course. The array is static. So the content is maintained between
>> calls.
>>
>> You need to know when to initialize it.
>>
>> Something like ...
>>
>>  public function getAllChildren($node,$level,$firstCall=True)
>>   {
>>       static $rootsarray=array();
>>       static $levelcount;
>>       if($firstCall) {
>>           $rootsarray=array();
>>       }
>>       $levelcount=$level;
>>       $child=self::getChild($node);
>>       if($child==''||$levelcount==0)
>>       {
>>           return 1;
>>       }
>>       else
>>       {
>>           $levelcount--;
>>           $rootsarray[]=$child;
>>           self::getAllChildren($child,$levelcount,False);
>>       }
>>       return $rootsarray;
>>
>>   }
>>
>>
>> --
>> -----
>> Richard Quadling
>> "Standing on the shoulders of some very clever giants!"
>> EE : http://www.experts-exchange.com/M_248814.html
>> Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731
>> ZOPA : http://uk.zopa.com/member/RQuadling
>
>

Why did you change the default to False? This now requires _ALL_ calls
to the method to be amended.

Unless you wanted to preserve the incorrect behaviour...

Hmmm. BC is a PITA.



-- 
-----
Richard Quadling
"Standing on the shoulders of some very clever giants!"
EE : http://www.experts-exchange.com/M_248814.html
Zend Certified Engineer : http://zend.com/zce.php?c=ZEND002498&r=213474731
ZOPA : http://uk.zopa.com/member/RQuadling