recursive function using php for getting level in binary tree - php

Question

I want to get level in the binary tree. I am getting already tree and insertion point but there is a problem in getting pair matching and level. The binary tree image is attached
here
how to stop recursive function after level 3.
my code is given below
function getTree($parent_id, $level){
global $conn;
$sql2 = "SELECT * FROM user WHERE parent_id='".$parent_id."' ORDER BY `rightorleft`";
$result2 = $conn->query($sql2);
$i=0;
static $calls=0;
if (mysqli_num_rows($result2) > 0)
{
echo "<ul>";
while ($row2 = mysqli_fetch_object($result2))
{
echo '<li>';
echo '<div><img src="images/user.png" width="40" height="40"><br>'.$row2->user_id.'</div>';
getTree($row2->id,$level++);
echo '</li>';
}
echo "</ul>";
}
}
I want to result only for 2 level like this

Answer 1

Try using $level as a counter to stop the recursion calls.
By calling the function with $level = 3 should give you the desired result.
function getTree($parent_id, $level)
{
global $conn;
// Stop when $level is 0 or less
if($level <= 0) return ;
$sql2 = "SELECT * FROM user WHERE parent_id='".$parent_id."' ORDER BY `rightorleft`";
$result2 = $conn->query($sql2);
$i = 0;
static $calls = 0;
if (mysqli_num_rows($result2) > 0)
{
echo "<ul>";
while ($row2 = mysqli_fetch_object($result2))
{
echo '<li>';
echo '<div><a href="#"><img src="images/user.png" width="40"
height = "40" >< br > '.$row2->user_id.' </ a ></ div > ';
// Recursively go deeper, use $level-1 here
getTree($row2->id,$level-1);
echo '</li>';
}
echo "</ul>";
}
}