- range: documentation ( source)
- array_walk: documentation ( source)
- array_pop: documentation ( source)
<?php
function sum() {
$list = array();
$prepare = function($value) use(&$prepare, &$list) {
if (is_array($value)) {
return array_walk($value, $prepare, $list);
} else {
$list[] = $value;
}
};
$args = func_get_args();
array_walk($args, $prepare, $list);
return addition(0, $list);
}
function addition($sum, array &$list) {
return empty($list) ? $sum : addition($sum + array_pop($list), $list);
}
$vars = range(1, 1000);
echo sum($vars);