using System;

using System.Drawing;

public class Program

{

    public static void Main()

    {

​

​

        Console.WriteLine("8 sectors");

        Console.WriteLine("P1(0,0) and P2(1,0): {0}", GetDirection(new Point(0, 0), new Point(1, 0)));

        Console.WriteLine("P1(0,0) and P2(1,1): {0}", GetDirection(new Point(0, 0), new Point(1, 1)));

        Console.WriteLine("P1(0,0) and P2(0,1): {0}", GetDirection(new Point(0, 0), new Point(0, 1)));

        Console.WriteLine("P1(0,0) and P2(-1,1): {0}", GetDirection(new Point(0, 0), new Point(-1, 1)));

        Console.WriteLine("P1(0,0) and P2(-1,0): {0}", GetDirection(new Point(0, 0), new Point(-1, 0)));

        Console.WriteLine("P1(1,1) and P2(-1,-1): {0}", GetDirection(new Point(0, 0), new Point(-1, -1)));

        Console.WriteLine("P1(1,1) and P2(0,-1): {0}", GetDirection(new Point(0, 0), new Point(0, -1)));

        Console.WriteLine("P1(1,1) and P2(1,-1): {0}", GetDirection(new Point(0, 0), new Point(1, -1)));

​

        //P1(1,1) and P2(0,1) returns Direction.West

        //P1(1,1) and P2(5,4) returns Direction.Northwest

        //P1(1,1) and P2(1,1) returns Direction.Undefined

        Console.WriteLine();

        Console.WriteLine("Test samples");

        Console.WriteLine("P1(1,1) and P2(0,1): {0}", GetDirection(new Point(1, 1), new Point(0, 1)));

        Console.WriteLine("P1(1,1) and P2(5,4): {0}", GetDirection(new Point(1, 1), new Point(5, 4)));

        Console.WriteLine("P1(1,1) and P2(1,1): {0}", GetDirection(new Point(1, 1), new Point(1, 1)));

​

    }

​

    static Direction GetDirection(Point start, Point end)

    {

        double dx = end.X - start.X;

        double dy = end.Y - start.Y;

        if (Math.Abs(dx) > Math.Abs(dy))

        {

            if (Math.Abs(dy / dx) <= tan_Pi_div_8)

            {

                return dx > 0 ? Direction.East : Direction.West;     

            }

            else if (dx > 0)

            {

                return dy > 0 ? Direction.Northeast : Direction.Southeast;

            }

            else 

            {

                return dy > 0 ? Direction.Northwest : Direction.Southwest;

            }

        }

​

        else if (Math.Abs(dy) > 0)

        {

            if (Math.Abs(dx / dy) <= tan_Pi_div_8)

            {

                return dy > 0 ? Direction.North : Direction.South;

            }

            else if (dy > 0)

            {

                return dx > 0 ? Direction.Northeast : Direction.Northwest;

            }

            else 

            {

                return dx > 0 ? Direction.Southeast : Direction.Southwest;

            }

        }

        else 

        {

            return Direction.Undefined;

        }

    }

    static readonly double tan_Pi_div_8 = Math.Sqrt(2.0) - 1.0;

}

​

public enum Direction

{

    North,

    South,

    East,

    West,

    Northeast,

    Northwest,

    Southeast,

    Southwest,

    Undefined

}