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CSharp · Console

/Program.cs

using System;

[Flags]
public enum DayOfWeek
{
	Sunday = 1 << 0,
	Monday = 1 << 1,
	Tuesday = 1 << 2,
	Wednesday = 1 << 3,
	Thursday = 1 << 4,
	Friday = 1 << 5,
	Saturday = 1 << 6
};

static class EnumerationExtension
{
	
	private static System.Random R { get; set; } = new System.Random();

	public static Enum Random(this Enum enumeration)
	{
		var type = enumeration.GetType();
		var strs = enumeration.ToString().Split(", ");
		var index = R.Next(strs.Length);
		return (Enum)Enum.Parse(type, strs[index]);
	}

}

public class Program
{
	
	public static void Main()
	{
		var mwf = DayOfWeek.Monday | DayOfWeek.Wednesday | DayOfWeek.Friday;
		Console.WriteLine($"Chosen days: {mwf}");
		
		for (int i = 0; i < 10; ++i)
			Console.WriteLine($"Random day: {mwf.Random()}");
	}
	
}