create dynamic tree using php

Question

I have a code for dynamic tree view using php mysql.

function fetchCategoryTreeList($parent = '', $user_tree_array = '') 
{
  // code here 
}

i just want ...like. i have a variable

$top = '1234';

now how to put in this function like

function fetchCategoryTreeList($parent = $top, $user_tree_array = '') 
{
  // code here 
}

if i put $top in this function then i got fatal error. Please help me

Answer 1

You cant assign default value as another variable to arguments. You can use constant instead

define("TOP", "1234");
function fetchCategoryTreeList($parent = TOP, $user_tree_array = '') 
{
  // code here 
}

Answer 2

If you really need a default dynamic value :

$top = '1234' ;

// Some code

function fetchCategoryTreeList($parent = '', $user_tree_array = '') 
{
  global $top ;
  if ( $parent == null || $parent == '' ) $parent = $top ;
  // code here 
}

But if the value is constant take a look at B Desai answer.