System.Globalization.GregorianCalendarHelper.GetDaysInMonth C# (CSharp) Method

        public int GetDaysInMonth(int year, int month, int era) {
            //
            // Convert year/era value to Gregorain year value.
            //
            year = GetGregorianYear(year, era);
            if (month < 1 || month > 12) {
                throw new ArgumentOutOfRangeException("month", Environment.GetResourceString("ArgumentOutOfRange_Month"));
            }
            int[] days = ((year % 4 == 0 && (year % 100 != 0 || year % 400 == 0)) ? DaysToMonth366: DaysToMonth365);
            return (days[month] - days[month - 1]);        
        }
    

        /*=================================GetDaysInMonth==========================
         **Action: Returns the number of days in the month given by the year and month arguments.
         **Returns: The number of days in the given month.
         **Arguments:
         **      year The year in Japanese calendar.
         **      month The month
         **      era     The Japanese era value.
         **Exceptions
         **  ArgumentException  If month is less than 1 or greater * than 12.
         **============================================================================*/


        public override int GetDaysInMonth(int year, int month, int era)
        {
            return(helper.GetDaysInMonth(year, month, era));
        }