rref

using System;
using System.IO;
using System.Globalization;
namespace MatrixRREF
{
    class MatrixRREF
    {
        public static void Main()
        {
            char esc;
            string str, path;
            int i, j, n, m;
            double[,] A;
            NumberFormatInfo nfi = new NumberFormatInfo();
            nfi.NumberDecimalSeparator = ".";
            Console.WriteLine("Podaj ścieżkę do pliku w którym chcesz zapisać wynik");
            path = Console.ReadLine();
            using(StreamWriter sw = new StreamWriter(path, true)) {
                do {
                    try {
                        Console.Clear();
                        Console.WriteLine("Sprowadzanie macierzy do postaci schodkowej zredukowanej");
                        Console.WriteLine();
                        Console.WriteLine("Podaj liczbe wierszy n=");
                        str = Console.ReadLine();
                        int.TryParse(str, out n);
                        Console.WriteLine("Podaj liczbe kolumn m=");
                        str = Console.ReadLine();
                        int.TryParse(str, out m);
                        A = new double[n, m];
                        for(i = 0; i < n; i++) {
                            Console.WriteLine("Wprowadz " + (i + 1).ToString(nfi) + ". wiersz macierzy");
                            for(j = 0; j < m; j++) {
                                str = Console.ReadLine();
                                double.TryParse(str, out A[i, j]);
                            }
                        }
                        A = rref(A);
                        for(i = 0; i < n; i++) {
                            for(j = 0; j < m; j++) {
                                Console.Write(A[i, j].ToString(nfi) + " , ");
                                sw.Write(A[i, j].ToString(nfi) + " , ");
                            }
                            Console.WriteLine();
                            sw.WriteLine();
                        }
                    } catch(System.IndexOutOfRangeException e) {
                        Console.WriteLine("Błędnie podany indeks");
                        Console.WriteLine(e.Message);
                    }
                    esc = (char)Console.ReadKey().Key;
                } while(esc != (char)ConsoleKey.Escape);
            }
        }
        private static double[,] rref(double[,] matrix)
        {
            int lead = 0, rowCount = matrix.GetLength(0), columnCount = matrix.GetLength(1);
            for (int r = 0; r < rowCount; r++) {
                if (columnCount <= lead) break;
                int i = r;
                while (matrix[i, lead] == 0) {
                    i++;
                    if (i == rowCount) {
                        i = r;
                        lead++;
                        if (columnCount == lead) {
                            lead--;
                            break;
                        }
                    }
                }
                for (int j = 0; j < columnCount; j++) {
                    double temp = matrix[r, j];
                    matrix[r, j] = matrix[i, j];
                    matrix[i, j] = temp;
                }
                double div = matrix[r, lead];
                if(div != 0)
                    for (int j = 0; j < columnCount; j++) matrix[r, j] /= div;
                for (int j = 0; j < rowCount; j++) {
                    if (j != r) {
                        double sub = matrix[j, lead];
                        for (int k = 0; k < columnCount; k++) matrix[j, k] -= (sub * matrix[r, k]);
                    }
                }
                lead++;
            }
            return matrix;
        }
    }
}