Extension method on Enum

gistfile1.cs

using System;

enum Direction { N, S, E, W}

static class X {
    public static double NominalDirectionInRadians(this Direction d)
    {
        var idx = (int)d;
        var directionCount = Enum.GetNames (typeof(Direction)).Length;
        var pct = (double) idx / directionCount;
        return pct * Math.PI * 2;
    }
            
    public static void Main(String[] args)
    {
        System.Console.WriteLine(Direction.S.NominalDirectionInRadians());
    }
}