Nullable value based vector : nullable « Data Type « C# / CSharp Tutorial

1. C# / CSharp Tutorial
2. Data Type
3. nullable

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


    public class Vector
    {
        public double? R = null;
        public double? Theta = null;

        public double? ThetaRadians
        {
            get
            {
                return (Theta * Math.PI / 180.0);
            }
        }

        public Vector(double? r, double? theta)
        {
            if (r < 0){
                r = -r;
                theta += 180;
            }
            theta = theta % 360;
            R = r;
            Theta = theta;
        }

        public static Vector operator +(Vector op1, Vector op2)
        {
            try
            {
                double newX = op1.R.Value * Math.Sin(op1.ThetaRadians.Value)+ op2.R.Value * Math.Sin(op2.ThetaRadians.Value);
                double newY = op1.R.Value * Math.Cos(op1.ThetaRadians.Value)+ op2.R.Value * Math.Cos(op2.ThetaRadians.Value);
                double newR = Math.Sqrt(newX * newX + newY * newY);
                double newTheta = Math.Atan2(newX, newY) * 180.0 / Math.PI;
                return new Vector(newR, newTheta);
            }
            catch
            {
                return new Vector(null, null);
            }
        }

        public static Vector operator -(Vector op1)
        {
            return new Vector(-op1.R, op1.Theta);
        }

        public static Vector operator -(Vector op1, Vector op2)
        {
            return op1 + (-op2);
        }

        public override string ToString()
        {
            string rString = R.HasValue ? R.ToString() : "null";
            string thetaString = Theta.HasValue ? Theta.ToString() : "null";
            return string.Format("({0}, {1})", rString, thetaString);
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            Vector v1 = new Vector(1, 2);
            Vector v2 = new Vector(1, 3);
            Console.WriteLine("{0} + {1} = {2}", v1, v2, v1 + v2);
            Console.WriteLine("{0} - {1} = {2}", v1, v2, v1 - v2);
        }
    }