find week ending date of last completed week

Question

For any given date, how would you find the week ending date of the last completed week, if your week runs from Sunday to Saturday?

Answer 1

DateTime StartOfWeek = DateTime.Today.AddDays(-(int)DateTime.Today.DayOfWeek);
DateTime EndOfLastWeek = StartOfWeek.AddDays(-1);

Answer 2

DateTime givenDate; // = ...
int daysToOffset = ((int)givenDate.DayOfWeek + 1) * -1;
DateTime lastDayOfLastCompletedWeek = givenDate.AddDays(daysToOffset);