using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace GeometryTasks
{
    public class Vector
    {
        public double X;
        public double Y;
        public double GetLength()
        {
            return Geometry.GetLength(this);
        }
        public Vector Add(Vector vector)
        {
            return Geometry.Add(this, vector);
        }
        public bool Belongs(Segment segment)
        {
            return Geometry.IsVectorInSegment(this, segment);
        }
    }
    public static class Geometry
    {
        public static double GetLenght(Vector vector)
        {
            return Math.Sqrt(vector.X * vector.X + vector.Y * vector.Y);
        }
        public static Vector Add(Vector vector1, Vector vector2)
        {
            return new Vector { X = vector1.X + vector2.X, Y = vector1.Y + vector2.Y };
        }
public static double GetLength(Segment segment)
        {
            return GetLength(Add(segment.Begin, new Vector { X = -segment.End.X, Y = -segment.End.Y }));
        }
        public static bool IsVectorInSegment(Vector vector, Segment segment)
        {
            return GetLength(Add(segment.Begin, new Vector { X = -segment.End.X, Y = -segment.End.Y }
        }
        public static bool IsVectorInSegment(Vector vector, Segment segment)
        {
            var lengthFromBeginToA = Math.Sqrt(Math.Pow(vector.X - segment.Begin.X, 2) +
            Math.Pow(vector.Y - segment.Begin.Y, 2));
            var lengthFromAtoEnd = Math.Sqrt(Math.Pow(segment.End.X - vector.X, 2) +
            Math.Pow(segment.End.Y - vector.Y, 2));
            return (lengthFromBeginToA + lengthFromAtoEnd == GetLength(segment));
        }
    }
    public class Segment
    {
        public Vector Begin;
        public Vector End;
        public double GetLength(Segment segment)
        {
            return Geometry.GetLength(segment);
        }
        public bool Contains(Vector vector)
        {
            return Geometry.IsVectorInSegment(vector, this);
        }
    }
}