enum Days { Sunday, Monday, Tuesday, Wednesday, Thursday, Friday, Saturday };
enum Months : byte { Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec }; 

Days today = Days.Monday;
int dayNumber =(int)today;
Console.WriteLine("{0} is day number #{1}.", today, dayNumber);

Months thisMonth = Months.Dec;
byte monthNumber = (byte)thisMonth;
Console.WriteLine("{0} is month number #{1}.", thisMonth, monthNumber);

Monday is day number #1.
Dec is month number #11.

Days meetingDay = Days.Monday;
//...
meetingDay = Days.Friday;

enum MachineState
{
  PowerOff = 0,
  Running = 5,
  Sleeping = 10,
  Hibernating = Sleeping + 5
}

[Flags]
enum Days2
{
  None = 0x0,
  Sunday = 0x1,
  Monday = 0x2,
  Tuesday = 0x4,
  Wednesday = 0x8,
  Thursday = 0x10,
  Friday = 0x20,
  Saturday = 0x40
}
class MyClass
{
  Days2 meetingDays = Days2.Tuesday | Days2.Thursday;
}

// Initialize with two flags using bitwise OR.
meetingDays = Days2.Tuesday | Days2.Thursday;

// Set an additional flag using bitwise OR.
meetingDays = meetingDays | Days2.Friday;

Console.WriteLine("Meeting days are {0}", meetingDays);
// Output: Meeting days are Tuesday, Thursday, Friday

// Remove a flag using bitwise XOR.
meetingDays = meetingDays ^ Days2.Tuesday;
Console.WriteLine("Meeting days are {0}", meetingDays);
// Output: Meeting days are Thursday, Friday

// Test value of flags using bitwise AND.
bool test = (meetingDays & Days2.Thursday) == Days2.Thursday;
Console.WriteLine("Thursday {0} a meeting day.", test == true ? "is" : "is not");
// Output: Thursday is a meeting day.

string s = Enum.GetName(typeof(Days), 4);
Console.WriteLine(s);

Console.WriteLine("The values of the Days Enum are:");
foreach (int i in Enum.GetValues(typeof(Days)))
  Console.WriteLine(i);

Console.WriteLine("The names of the Days Enum are:");
foreach (string str in Enum.GetNames(typeof(Days)))
  Console.WriteLine(str);