using System;

using System.Text.RegularExpressions;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Hello Unique :)");

        Console.WriteLine("---------------");

        Console.WriteLine("TASK 1");

        Console.WriteLine("---------------");

        DateTime today = DateTime.Now;

        DateTime index;

        for (int i = 0; i < 12; i++)

        {

            if (i != 2)

            {

                index = DateHelper.GetDateForLastDayOfWeek(DayOfWeek.Monday, today.AddDays(-i * 7));

                Console.WriteLine(i + 1 + ") " + index.ToString(DateHelper.AU_DATETIME_FORMAT));

            }

        }

​

        Console.WriteLine();

        Console.WriteLine("Please Enter two-digit number to find its position in pi:");

        Console.WriteLine("(e.g. 15 has position 3 in 3.14159.....)");

        string pattern = Console.ReadLine();

        // Check if the input is two-digit number.

        if (pattern.Length == 2 && Regex.IsMatch(pattern, @"^\d+$"))

        {

            int position = Lib.PositionSearchInPie(pattern);

            // Display the result.

            if (position < 0)

                Console.WriteLine(pattern + " was not found");

            else

                Console.WriteLine(pattern + " found at digit " + position.ToString());

        }

        else

        {

            Console.WriteLine("Error: You entered '{0}' is not a two-digit number. Please try again.", pattern);

        }

    }

​

    public static class DateHelper

    {

        public static string AU_DATETIME_FORMAT = "dd MMMM, yyyy";

        public static DateTime GetDateForLastDayOfWeek(DayOfWeek DOW, DateTime DATE)

        {

            int adjustment = ((int)DATE.DayOfWeek < (int)DOW ? 7 : 0);

            return DATE.AddDays(0 - (((int)(DATE.DayOfWeek) + adjustment) - (int)DOW));

        }

    }

​

    public static class Lib

    {

        public static Regex REG_EXP = new Regex("[^0-9]");

        public static int PositionSearchInPie(string pattern)

        {

            // Remove all non-digits.

            pattern = REG_EXP.Replace(pattern, "");

            string Pi = Math.PI.ToString().Replace(".", "");

            // Search for the pattern.

            return Pi.IndexOf(pattern);

            ;

        }

    }

}