if ($month == 2) 
    {
        if ( ( $year % 4 == 0 )         # normal leap year
         &&  ( ( $year % 100 != 0 )     # century year
               || ( $year % 400 == 0 )  # leap century
             )
           )
        {
            return 29;
        }
    }

##</code><code>##

if( 2 == $month )
{
    return 29 if 0 == $year % 4 and 0 != $year % 100 
                 or 0 == $year % 400;
}