FoldAndSum_12.05.2016

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

namespace FoldAndSum_12._05._2016
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] numbs = Console.ReadLine().Split(' ').Select(int.Parse).ToArray();

            int k = numbs.Length / 4; // example: if numbs.Length = 8 => k = 2;
            int[] arrStartEnd = new int[2 * k]; //if numbs.Length = 8 => []arrStartEnd.Length = 4;
            int[] arrMiddle = new int[2 * k]; // the middle items of []numbs
            int[] arrSum = new int[2 * k];

            ArrayEnd(numbs, arrStartEnd, k);
            ArrayStart(numbs, arrStartEnd, k);
            ArrayMiddle(numbs, arrMiddle, k);
            ArraySummation(arrStartEnd, arrMiddle, arrSum, k);

           Console.WriteLine(string.Join(" ", arrSum));
        }

        static int[] ArrayEnd(int[] numbs, int[] arrStartEnd, int k) // this method saves reversed nums LAST items in arrStartEnd
        {
            int[] arrTemp = new int[k];

            for (int i = 0; i < k; i++)
            {
                arrTemp[i] = numbs[(3 * k) + i];
            }

            for (int iRev = 0; iRev < k - 1; iRev++) // reverse of []arrTemp
            {
                int old = arrTemp[iRev];
                arrTemp[iRev] = arrTemp[k - 1 - iRev];
                arrTemp[k - 1 - iRev] = old;
            }

            for (int iSave = 0; iSave < k; iSave++) // saving reversed []arrTmp values in []arrStartEnd.
            {
                arrStartEnd[k + iSave] = arrTemp[iSave];
            }
                return arrStartEnd;
        }

        static int[] ArrayStart(int[] numbs, int[] arrStartEnd, int k) // this method saves reversed nums FIRST items in arrStartEnd
        {
            int[] arrTemp = new int[k];

            for (int i = 0; i < k; i++)
            {
                arrTemp[i] = numbs[i];
            }

            for (int iRev = 0; iRev < k - 1; iRev++) // reverse of []arrTemp
            {
                int old = arrTemp[iRev];
                arrTemp[iRev] = arrTemp[k - 1 - iRev];
                arrTemp[k - 1 - iRev] = old;
            }

            for (int iSave = 0; iSave < k; iSave++) // saving reversed []arrTmp values in []arrStartEnd.
            {
                arrStartEnd[iSave] = arrTemp[iSave];
            }
            return arrStartEnd;
        }

        static int[] ArrayMiddle(int[] numbs, int[] arrMiddle, int k)
        {
            for (int iMiddle = k; iMiddle < 3 * k; iMiddle++)
            {
                arrMiddle[iMiddle - k] = numbs[iMiddle];
            }
            return arrMiddle;
        }

        static int[] ArraySummation(int[] arrStartEnd, int[] arrMiddle, int[] arrSum, int k)
        {
            for (int iSum = 0; iSum < 2 * k; iSum++)
            {
                arrSum[iSum] = arrStartEnd[iSum] + arrMiddle[iSum];
            }
            return arrSum;
        }

    }
}