Browary mają być zimne

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

namespace INT
{
    class UserMatrix
    {
        private double?[,] Tab;
        private int NrOfNodes;

        public UserMatrix()
        {
            Console.WriteLine("Podaj ilość węzłów:");
            NrOfNodes = Convert.ToInt32(Console.ReadLine());
            Tab = new double?[NrOfNodes, 2];
            Console.Clear();
        }

        public void FillTable()
        {
            for (int x = 0; x < NrOfNodes; x++)
            {
                ShowTable();

                for (int y = 0; y < 2; y++)
                {
                    if (y == 0)
                    {
                        Console.WriteLine($"\nPodaj {x + 1} węzeł x: ");
                        Tab[x, y] = Convert.ToDouble(Console.ReadLine());
                    }
                    else if (y == 1)
                    {
                        Console.WriteLine($"\nPodaj {x + 1} węzeł y: ");
                        Tab[x, y] = Convert.ToDouble(Console.ReadLine());
                    }
                }
            }
        }

        public void ShowTable()
        {
            Console.Clear();

            for (int x = 0; x < NrOfNodes; x++)
            {
                for (int y = 0; y < 2; y++)
                {
                    if (Tab[x, y] == null)
                    {
                        Console.Write("- ");

                    }
                    else
                    {
                        Console.Write("{0} ", Tab[x, y]);
                    }
                }
                Console.WriteLine();
            }
        }

        public int ReturnNodes() => NrOfNodes;
        public double?[,] ReturnMatrix() => Tab;
    }

    class ProgramMatrix
    {
        private double[,] macierz;
        private int NrOfNodes;
        private double max;
        private int rownanie;

        public ProgramMatrix(int nodes, double?[,] matrix)
        {
            macierz = new double[nodes, nodes + 1];
            NrOfNodes = nodes;

            for (int x = 0; x < nodes; x++)
            {
                macierz[x, 0] = 1;
                macierz[x, nodes] = matrix[x, 1].Value;
            }

            for (int x = 0; x < nodes; x++)
            {
                for (int y = 1; y < nodes; y++)
                {
                    macierz[x, y] = macierz[x, y - 1]*matrix[x, 0].Value;
                }
            }
        }

        public void MakeMath()
        {
            for (int kolumna = 0; kolumna < NrOfNodes; kolumna++)
            {
                double max = macierz[kolumna, kolumna];
                rownanie = kolumna;

                for (int wiersz = kolumna; wiersz < NrOfNodes; wiersz++)
                {
                    if (Math.Abs(macierz[wiersz, kolumna]) > max)
                    {
                        max = Math.Abs(macierz[wiersz, kolumna]);
                        rownanie = wiersz;
                    }
                }

                if (Math.Abs(max) < 1E-20)
                {
                    throw new Exception();
                }

                for (int x = kolumna; x < NrOfNodes + 1; x++)
                {
                    double zmienna_tymczasowa = macierz[kolumna, x];
                    macierz[kolumna, x] = macierz[rownanie, x];
                    macierz[rownanie, x] = zmienna_tymczasowa;
                }

                double pole = macierz[kolumna, kolumna];

                for (int x = kolumna; x < NrOfNodes + 1; x++)
                {
                    double zmienna_tymczasowa = macierz[kolumna, x] / pole;
                    macierz[kolumna, x] = zmienna_tymczasowa;
                }

                for (int x = 0; x < NrOfNodes; x++)
                {
                    if (x != kolumna)
                    {
                        double g = macierz[x, kolumna];
                        for (int y = kolumna; y < NrOfNodes+ 1; y++)
                        {
                            macierz[x, y] -= (g * macierz[kolumna, y]);
                        }
                    }
                }
            }
        }

        public void SwapElements(int x1, int y1, int x2, int y2)
        {
            double temp = macierz[x1, y1];
            macierz[x1, y1] = macierz[x2, y2];
            macierz[x2, y2] = temp;
        }

        public void ShowTable()
        {
            for (int x = 0; x < NrOfNodes; x++)
            {
                for (int y = 0; y < NrOfNodes + 1; y++)
                {
                    Console.Write($"{macierz[x, y]} ");
                }
                Console.WriteLine();
            }
        }

        public void ShowResult()
        {
            double x, p;

            Console.WriteLine("\nPodaj x: ");
            x = Convert.ToDouble(Console.ReadLine());
            p = macierz[NrOfNodes - 1,NrOfNodes];

            for (int y = NrOfNodes - 2; y >= 0; y--)
            {
                p = x * p + macierz[y,NrOfNodes];
            }

            Console.WriteLine($"\nWynik to y={p}");
        }

    }

    class Program
    {
        static void Main(string[] args)
        {
            var user = new UserMatrix();
            user.FillTable();
            var program = new ProgramMatrix(user.ReturnNodes(), user.ReturnMatrix());
            Console.Clear();
            Console.WriteLine("Macierz przed obliczeniami: ");
            program.ShowTable();

            Console.WriteLine("\nMacierz po obliczeniach: ");
            try
            {
                program.MakeMath();
                program.ShowTable();
                program.ShowResult();
            }
            catch
            {
               Console.Clear();
               Console.WriteLine("Macierz Osobliwa");
            }

        }
    }
}