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's my algorithm:

1. Find the number of days until the upcoming Friday.
2. Initialize a counter and set it to 1. Subtract seven days from the date returned from [1], then compare the month from the date returned against the date returned from (1).
   3. If the months are not equal, return the counter from [2].
   4. If the months are equal, recurse into [2] and add 1 to the counter created in [2].

The counter will give you the nth Friday of the month for that date (or its upcoming Friday).