PHP:
function calculator(int $n1, int $n2, string $type): ?int
{
if (!empty($n1) && !empty($n2) && !empty($type)){
if ($type == "*"){
$result = $n1 * $n2;
}
if ($type == "/"){
$result = $n1 / $n2;
}
if ($type == "-"){
$result = $n1 - $n2;
}
if ($type == "+"){
$result = $n1 + $n2;
}
return $result;
}
return null;
}
echo calculator(2, 4, '+');