string firstDayOfThisQuarter = DateTime.Now.AddMonths(0-(DateTime.Now.Month - 1)%3).ToString("yyyy-MM-01");
Console.WriteLine(" The first of the quarter 1 Day as follows: {0}",firstDayOfThisQuarter);
string lastDayOfThisQuarter = DateTime.Parse(DateTime.Now.AddMonths(3 - ((DateTime.Now.Month - 1)%3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString();
string lastDayOfThisQuarter2 = DateTime.Parse(DateTime.Now.AddMonths(3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToString("yyyy-MM-dd");
Console.WriteLine(" The end of the quarter 1 Day as follows: {0}", lastDayOfThisQuarter);
Console.WriteLine(" The end of the quarter 1 Day as follows: {0}", lastDayOfThisQuarter2);
string firstDayOfNextQuarter = DateTime.Now.AddMonths(3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01");
string lastDayOfNextQuarter = DateTime.Parse(DateTime.Now.AddMonths(6 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString();
Console.WriteLine(" Next quarter 1 Day as follows: {0}", firstDayOfNextQuarter);
Console.WriteLine(" At the end of the next quarter 1 Day as follows: {0}", lastDayOfNextQuarter);
string firstDayOfLastQuarter = DateTime.Now.AddMonths(-3 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01");
string lastDayOfLastQuarter = DateTime.Parse(DateTime.Now.AddMonths(0 - ((DateTime.Now.Month - 1) % 3)).ToString("yyyy-MM-01")).AddDays(-1).ToShortDateString();
Console.WriteLine(" Last quarter's no 1 Day as follows: {0}", firstDayOfLastQuarter);
Console.WriteLine(" The end of last quarter 1 Day as follows: {0}", lastDayOfLastQuarter);