function closestToZero(array $numbers) {
    if (empty($numbers)) {
        return 0;
    }

    $closest = $numbers[0];

    foreach ($numbers as $number) {
        if (abs($number) < abs($closest)) {
            $closest = $number;
        } elseif (abs($number) == abs($closest)) {
            $closest = max($number, $closest);
        }
    }
    return $closest;
}