判断是几季度的算法

        private static string TimeToQuarterString(string time)
        {
            DateTime t = DateHelper.ToDateTime(time);
            string Y = time.Substring(0, 4);
            int  y = Convert.ToInt32(Y);
            if (t.CompareTo(new DateTime(y, 1, 1)) >= 0 && t.CompareTo(new DateTime(y, 3, 31)) <= 0)
                return Y + "年第一季度";
            else if (t.CompareTo(new DateTime(y, 4, 1)) >= 0 && t.CompareTo(new DateTime(y, 6, 30)) <= 0)
                return Y + "年第二季度";
            else if (t.CompareTo(new DateTime(y, 7, 1)) >= 0 && t.CompareTo(new DateTime(y, 9, 30)) <= 0)
                return Y + "年第三季度";
            else if (t.CompareTo(new DateTime(y, 10, 1)) >= 0 && t.CompareTo(new DateTime(y, 12, 31)) <= 0)
                return Y + "年第四季度";
            else
                return "";
        }