Question

How to find the dates of the last Fridays of each month of a given year in C#

Answer 1

using System;
using System.Globalization;
using System.Collections.Generic;

public class LastFridaysOfYearProgram
{
    // Return all last Fridays of each month in a given year
    private static IEnumerable<DateTime> LastFridaysOfYear(int year) {
        for (var month = 1; month <= 12; month++) {
            // Last day of the month
            var date = new DateTime(year, month, 1)
                .AddMonths(1)
                .AddDays(-1);

            // Walk backward to Friday
            while (date.DayOfWeek != DayOfWeek.Friday) {
                date = date.AddDays(-1);
            }

            yield return date;
        }
    }

    public static void Main(string[] args)
    {
        int year = (args.Length > 0)
            ? int.Parse(args[0])
            : 2026;

        foreach (var date in LastFridaysOfYear(year)) {
            Console.WriteLine(date.ToString("d", CultureInfo.InvariantCulture));
        }
    }
}


/*
run:

01/30/2026
02/27/2026
03/27/2026
04/24/2026
05/29/2026
06/26/2026
07/31/2026
08/28/2026
09/25/2026
10/30/2026
11/27/2026
12/25/2026

*/

 

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