Alternando colores en tablas

<?php
$row_color = array('red','green');
$color_index = 0;

$meal = array('breakfast' => 'Walnut Bun',

              'lunch' => 'Cashew Nuts and White Mushrooms',

              'snack' => 'Dried Mulberries',

              'dinner' => 'Eggplant with Chili Sauce');

print "<table>\n";

foreach ($meal as $key => $value) {

    print '<tr bgcolor="' . $row_color[$color_index] . '">';

    print "<td>$key</td><td>$value</td></tr>\n";

    // This switches $color_index between 0 and 1

    $color_index = 1 - $color_index;

}

print '</table>';

?>