Explain below code

Question

<?php
$taran = 0;
function num($a)
{
global $taran;
$taran ++;
if ($a<1)
return;
else
num($a-1);
num($a-3);
}
num(5);
echo ($taran);
?>

Answer 1

the num function is a recursive function witch increments the value of $taran with 1 with every pass and exits when $a<1