using System;
using System.IO;
using System.Globalization;
namespace MatrixInverse
{
    static class ExtensionClass
    {
        public static void PrintMatrix(this StreamWriter sw,double[,] A)
        {
            int m = A.GetLength(0);
            int n = A.GetLength(1);
            NumberFormatInfo nfi = new NumberFormatInfo();
            for(int i = 0;i < m;i++)
            {
                for(int j = 0;j < n;j++)
                    sw.Write("{0} ",A[i,j].ToString(nfi));
                sw.WriteLine();
            }
            sw.WriteLine();
        }
    }
    class MatrixInverse
    {
        public const double EPS = 1e-12;
        public static void Main()
        {
            char esc;
            string str,path;
            int i,j,n;
            double[,] A;
            uint error;
            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
                {
                    Console.Clear();
                    Console.WriteLine("Odwracanie macierzy");
                    Console.WriteLine();
                    Console.WriteLine("Podaj rozmiar macierzy n=");
                    str = Console.ReadLine();
                    int.TryParse(str,out n);
                    A = new double[n,n];
                    for(i = 0;i < n;i++)
                    {
                        Console.WriteLine("Wprowadz " + i.ToString(nfi) + ". wiersz macierzy");
                        for(j = 0;j < n;j++)
                        {
                            str = Console.ReadLine();
                            double.TryParse(str,out A[i,j]);
                        }
                    }
                    PrintMatrix(A);
                    Inverse(A,EPS,out error);
                    sw.PrintMatrix(A);
                    PrintMatrix(A);
                    sw.WriteLine(error.ToString(nfi));

                    esc = (char)Console.ReadKey().Key;
                }
                while(esc != (char)ConsoleKey.Escape);
            }
        }
        public static void PrintMatrix(double[,] A)
        {
            int m = A.GetLength(0);
            int n = A.GetLength(1);
            NumberFormatInfo nfi = new NumberFormatInfo();
            for(int i = 0;i < m;i++)
            {
                for(int j = 0;j < n;j++)
                    Console.Write("{0} ",A[i,j].ToString(nfi));
                Console.WriteLine();
            }
            Console.WriteLine();
        }
        public static void Inverse(double[,] A,double eps,out uint error)
        {
            int n;
            if(A.GetLength(0) != A.GetLength(1))
            {
                error = 2;
                return;
            }
            n = A.GetLength(0);
            int[] M = new int[n];
            double maxA,d,e;
            int k;
            error = 0;
            for(int i = 0; i < n;i++)
            {
                maxA = 0;
                k = i;
                for(int j = i; j < n;j++)
                {
                    d = A[j,i];
                    if(Math.Abs(maxA) < Math.Abs(d))
                    {
                        maxA = d;
                        k = j;
                    }
                }
                if(Math.Abs(maxA) < eps)
                {
                    error = 1;
                    return;
                }
                M[i] = k;
                A[k,i] = 1;
                for(int j = 0;j < n;j++)
                {
                    d = A[k,j]/maxA;
                    A[k,j] = A[i,j];
                    A[i,j] = d;
                }
                for(int j = 0;j < n;j++)
                    if(j != i)
                    {
                        d = A[j,i];
                        A[j,i] = 0;
                        for(int l = 0;l < n;l++)
                        {
                            e = d*A[i,l];
                            A[j,l] -= e;
                        }
                    }
            }
            for(int i = n-1;i >= 0;i--)
            {
                k = M[i];
                if(k != i)
                    for(int j=0;j < n;j++)
                    {
                        d = A[j,i];
                        A[j,i] = A[j,k];
                        A[j,k] = d;
                    }
            }
        }
    }
}