PHP 可変長引数

<?php

//function sum($a, $b, $c)
function sum(…$numbers)
{
//return $a + $b + $c;
$total = 0;
foreach($numbers as $number){
$total += $number;
}
return $total;
}

echo sum(1,3,5) . PHP_EOL;
echo sum(4,2,5,1) . PHP_EOL;