Nearest completed quarter

Question

Is there a C# function which will give me the last day of the most recently finished Quarter given a date?

For example,

var lastDayOfLastQuarter = So         


        

Answer 1

Try this:
The AddMonths(-(d.Month-1) % 3)) moves the datevalue to the equivilent day of the first month in the quarter, and then the AddDays (-day) moves back to the last day of the preceding month.

  DateTime d = Datetime.Now;
  DateTime lastDayOfLastQuarter = d.AddMonths(-((d.Month-1)%3)).AddDays(-d.Day);