using System;

using System.Collections.Generic;

using System.Linq;

​

​

[Flags] //Flags attribute creates a bitmask out of the enum.

public enum Day : ulong { None = 0, Monday = 1, Tuesday = 2, Wednesday = 4, Thursday = 8, Friday = 16, Saturday = 32, Sunday = 64 }

​

public static class EnumExtensions

{

    public static List<string> ToList(this Enum item)

    {

        return item.ToString().Split(',').Select(m => m.Trim()).ToList();   

    }

    public static bool Contains(this Enum item, Enum value)

    {

        return item.HasFlag(value); 

    }

    //Is this worth it?

    public static ulong Take(this ulong item, int amount)

    {

        var bits = new List<ulong>();

        for(int i = 0; i < 64 && bits.Count < amount; ++i)

        {

            var check = 1ul << i; //2^i

            if ((item & check) == check)

                bits.Add(check);

        }

        var result = bits.Aggregate((context, content) => context | content);       

        return result;  

    }

}

​

public class Program

{       

    public static void Main()

    {

        var freeDays = Day.Monday | Day.Tuesday | Day.Friday;

        var onSaturday = freeDays.Contains(Day.Saturday) ? "Yes" : "No";

        Console.WriteLine(String.Format("Am I free on Saturday? {0}", onSaturday));

        var onTuesday = freeDays.Contains(Day.Tuesday) ? "Yes" : "No";

        Console.WriteLine(String.Format("Am I free on Tuesday? {0}", onTuesday));

        //Use EnumExtensions to get the list of

        foreach (var item in freeDays.ToList())

        {

            Console.WriteLine(item);

        }

        //Print csv

        Console.WriteLine(freeDays);

        Console.WriteLine((ulong) freeDays);

        var val = (Day) ((ulong)freeDays).Take(2);

        Console.WriteLine(val);

    }

}