Rohit Gupta

   1: public static DateTime NextQuarterEnd(this DateTime date)

   2: {

   3:     IEnumerable<DateTime> candidates =

   4:         QuartersInYear(date.Year).Union(QuartersInYear(date.Year + 1));

   5:     return candidates.Where(d => d.Subtract(date).Days > 0).First();            

   6: }

   7:  

   8: public static IEnumerable<DateTime> QuartersInYear(int year)

   9: {

  10:     return new List<DateTime>() {

  11:             new DateTime(year, 3, 31),

  12:             new DateTime(year, 6, 30),

  13:             new DateTime(year, 9, 30),

  14:             new DateTime(year, 12, 31),

  15:             };

  16: }

   1: public static DateTime PreviousQuarterEnd(this DateTime date)

   2: {

   3:     IEnumerable<DateTime> candidates =

   4:         QuartersInYear(date.Year).Union(QuartersInYear(date.Year - 1));

   5:     return candidates.Where(d => d <= date).OrderBy(d => d).Last();

   6: }

   1: public static DateTime NextMonthEnd(this DateTime date)

   2: {

   3:     return new DateTime(date.Year, date.Month, 1).AddMonths(2).AddDays(-1);

   4: }

   1: public static DateTime PreviousMonthEnd(this DateTime date)

   2: {

   3:     return new DateTime(date.Year, date.Month, 1).AddDays(-1);

   4: }