26.cs

using System;

namespace Rextester
{
    public class ArrayHelper
    {

        int[] _result;
        public int[] result
        {
            get { return _result; }
            set { this._result = value; }
        }

        public ArrayHelper(int _n)
        {
            result = new int[_n];
        }
        public ArrayHelper(int _n, int[]_r)
        {
            result = _r;
        }
        
        public static ArrayHelper operator +(ArrayHelper x, int[] y)
        {
            if (x.result.Length == y.Length)
            {
                var h = new ArrayHelper(x.result.Length);

                int[] z = new int[x.result.Length];

                for (int i = 0; i < x.result.Length; i++)
                {
                    z[i] = x.result[i] + y[i];
                }
                return new ArrayHelper(x.result.Length, z);
            }
            return null;
        }
        public static ArrayHelper operator +(ArrayHelper x, ArrayHelper y)
        {

            if (x.result.Length == y.result.Length)
            {

                var h = new ArrayHelper(x.result.Length);

                int[] z = new int[x.result.Length];

                for (int i = 0; i < x.result.Length; i++)
                {
                    z[i] = x.result[i] + y.result[i];
                }
                return new ArrayHelper(x.result.Length, z);
            }
            return null;
        }
    }

    public class Program
    {
        public static void Main(string[] args)
        {
            //Your code goes here
            Console.WriteLine("Hello, world!");

            const int n = 5;
            int[] a = new int[n] { 1, 2, 3, 4, 5 };
            int[] b = new int[n] { 5, 4, 3, 2, 1 };

            var h1 = new ArrayHelper(n);
            var h2 = new ArrayHelper(n);
            h1.result = a;
            h2.result = b;

            // c = Add(a, b);
            h1 = h1 + h2;

            foreach (var item in h1.result)
            {
                Console.WriteLine(item.ToString());
            }

        }
    }
}