Return array from Recursive - Php

Question

When browsing the binary tree I want to return an array of recursive functions. In particular when an element in binary tree reaching conditions (if statement) is inserted into the array. After all, the element returns an array of all. My code not work !??

function tree_view($clear_static = false,$conn,$index)
{
    static $count = 0;
    if ($clear_static) {
        $count = 0;
    }
    $q=mysql_query("SELECT user_id FROM thanhvien WHERE gioithieu='".$index."'",$conn);

    while($arr=mysql_fetch_assoc($q)) 
    { 
        if (truongban($conn,$arr["user_id"],1)==true){
            $mang[$count]=$arr["user_id"];
            $count++;
        }
        tree_view(false,$conn,$arr["user_id"]); 
    } 
    return $mang;
} 
$mang1=tree_view (true,$conn,anloc);
print_r($mang1);

Do you want to really return 'array of recursive functions'? Not just simple data? — SteAp
– SteAp, Commented Feb 25, 2012 at 0:30
You want to return your function AM array, not an array of functions. — SteAp
– SteAp, Commented Feb 25, 2012 at 14:28

José Ernesto Lara Rodríguez · Accepted Answer · 2012-02-24 16:33:27Z

1

Well, the problem I see is that you are not doing anything with the array returned from the recursive call, here in this line:

tree_view(false,$conn,$arr["user_id"]);

I would recommend including both the array and the count on the method parameters (using a static variable is not recommended). So it would be like this:

function tree_view($conn, $index, $mang, &$count)
{
    $q=mysql_query("SELECT user_id FROM thanhvien WHERE gioithieu='".$index."'",$conn);

    while($arr=mysql_fetch_assoc($q)) 
    { 
        if (truongban($conn,$arr["user_id"],1)==true){
            $mang[$count]=$arr["user_id"];
            $count++;
        }
        tree_view($conn,$arr["user_id"], $mang, $count); 
    } 
    return $mang;
}

And you would invoke your method like this:

$mang1[0] = "";
$count = 0;
$mang1 = tree_view ($conn, anloc, $mang1, $count); print_r($mang1);

edited Feb 24, 2012 at 16:33

answered Feb 24, 2012 at 6:04

José Ernesto Lara Rodríguez

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3 Comments

hitachitellme Over a year ago

Thank you!me was trying to how to your, but it only display Array ( [0] => thidotn1 ). If exactly does it must be displayed 10 element

José Ernesto Lara Rodríguez Over a year ago

Oops, sorry, I forgot to pass $count by reference. I edited the code, it should work now.

hitachitellme Over a year ago

when i edit your code. It display " Array ( [0] => [9] => thidotn1 ) " what prolem with it ! Thank you for help

SteAp · Accepted Answer · 2012-02-25 00:39:51Z

First $mang isn't initialized, but likely should be:

  // Always initialize variables - good style
  $mang = array();

Instead of passing this ugly $count variable, just append newly discovered data:

  // Will append the right side value as a new last element to $mang
  $mang[] = $arr["user_id"];

Next, you need to pass the variable $anloc:

  $mang1=tree_view ( true, $conn, $anloc );

This version might work better:

function tree_view($conn, $index, $mang ) {

    $q=mysql_query(  'SELECT user_id '
                   . '  FROM thanhvien '
                   . ' WHERE gioithieu = "' . mysql_real_escape_string ( $index ) . '"', 
                   $conn 
                  );

    while( $arr = mysql_fetch_assoc( $q ) ) {

        // better compare type-safe
        if ( true === truongban( $conn, $arr["user_id"], 1 ) ){

            // append found element
            $mang[ ] = $arr["user_id"];

        }

        tree_view( $conn, $arr["user_id"], $mang ); 

    } 

    return $mang;

} // tree_view

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