Question

I’m writing a function for exploring an XML document, and need to use recursion. It’s not quite behaving how I wanted, so started running some tests.

<?php

$i=0;
function recursion(){
    $i++;
    if($i < 10){recursion();}
    echo $i;
    }
recursion();
?> 

This generates a 500 Internal Server Error. Seems like I’m mishandling something – can someone help me out?

Answer 1

$i inside the function does not refer to the global variable $i, so it is always 1 and the script overflows the stack.

You could make $i global, but it’s much better to pass it as an argument:

function recursion($i){
    $i++;
    if($i < 10){recursion($i);}
    echo $i;
}

recursion(0);