static class ExtensionMethod
    {
        public static double GetLength(this Vector vector)
        {
            return Math.Sqrt(Math.Pow(vector.X, 2) + Math.Pow(vector.Y, 2));
        }
        public static double GetLength(this Segment segment)
        {
            return Math.Sqrt(Math.Pow(segment.Begin.X - segment.End.X, 2) + Math.Pow(segment.Begin.Y - segment.End.Y, 2));
        }
        public static Vector Add(this Vector firstVector, Vector secondVector)
        {
            return new Vector() { X = firstVector.X + secondVector.X, Y = firstVector.Y + secondVector.Y };
        }
        public static bool Belongs(this Vector vector, Segment segment)
        {
            return (GetLength(segment) == GetLength(new Vector() { X = vector.X - segment.Begin.X, Y = vector.Y - segment.Begin.Y }) + GetLength(new Vector() { X = vector.X - segment.End.X, Y = vector.Y - segment.End.Y }));
        }
        public static bool Contain(this Segment segment, Vector vector)
        {
            return (GetLength(segment) == GetLength(new Vector() { X = vector.X - segment.Begin.X, Y = vector.Y - segment.Begin.Y }) + GetLength(new Vector() { X = vector.X - segment.End.X, Y = vector.Y - segment.End.Y }));
        }
    }