class

public static int CountOffDays (DateTime start,DateTime end)
        {
            int res = 0;
            DateTime dt;
            dt = start;
            while (dt <= end)
            {
                if (dt.DayOfWeek == DayOfWeek.Friday || dt.DayOfWeek == DayOfWeek.Saturday)
                {
                    res = 1 + res;
                   
                }
                dt = dt.AddDays(1);

            }
            return res;
        }

        public static DateTime[] OffDays(DateTime start, DateTime end)
        {
            //int ii = CountOffDays(start,end);
            DateTime[] res = new DateTime[CountOffDays(start, end)];
            DateTime dt;int i = 0;
            dt = start;
            while (dt <= end)
            {
                if (dt.DayOfWeek == DayOfWeek.Friday || dt.DayOfWeek == DayOfWeek.Saturday)
                {
                    
                    res[i] = dt;
                    i = i + 1;
                    
                }
                dt = dt.AddDays(1);
                

            }
            return res;
        }