How to find the 3rd Friday in a month with C#?

Question

Given a date (of type DateTime), how do I find the 3rd Friday in the month of that date?

Answer 1

Here is my two cents... An optimized solution without unnecessary loops or tests :

public static DateTime ThirdFridayOfMonth(DateTime dateTime)
{
    int day = dateTime.Day;
    return dateTime.AddDays(21 - day - ((int)dateTime.DayOfWeek + 37 - day) % 7);
}