using System;

[Flags]

public enum DaysOfWeek

{

    Sunday = 1 << 0,

    Monday = 1 << 1,

    Tuesday = 1 << 2,

    Wednesday = 1 << 3,

    Thursday = 1 << 4,

    Friday = 1 << 5,

    Saturday = 1 << 6,

}

​

public class Program

{

    public static void Main()

    {

        var days = (DaysOfWeek)6;

        var dayStandard = DayOfWeek.Sunday;

        var mask = 1 << (int)dayStandard;

        var maskOwn = (DaysOfWeek)Enum.ToObject(typeof(DaysOfWeek), mask);

        if (days.HasFlag(maskOwn))

            Console.WriteLine("+");

            //Do whatever;

    }

}