matrix_inverse

using System;
using System.IO;
using System.Globalization;
namespace MatrixInverse
{
	class MatrixInverse
	{
		public static void Main()
		{
			char esc;
			string str,path;
			int i,j,n;
			double[,] A;
			double d;
			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+1,2*n+1];
					for(i = 1;i <= n;i++)
					{
						Console.WriteLine("Wprowadz " + i.ToString(nfi) + ". wiersz macierzy");
						for(j = 1;j <= n;j++)
						{
							str = Console.ReadLine();
							double.TryParse(str,out A[i,j]);
						}
					}
					Inverse(A,n,out d);
					sw.WriteLine(d.ToString(nfi));
					for(i = 1;i <= n && d != 0.0 ;i++)
					{
						for(j = n + 1;j <= 2*n;j++)
						{
							Console.Write(A[i,j].ToString(nfi)+" , ");
							sw.Write(A[i,j].ToString(nfi) + " , ");
						}
						Console.WriteLine();
						sw.WriteLine();
					}

					esc = (char)Console.ReadKey().Key;
				}
				while(esc != (char)ConsoleKey.Escape);
			}
		}
		public static void Inverse(double[,] A,int n,out double d)
		{
			int i,j,k,m;
			double s,t,temp;
			d = 1.0;
			for(i = 1;i <= n;i++)
				for(j = n+1;j <= 2*n;j++)
					if(i == j - n)
						A[i,j] = 1.0;
					else
						A[i,j] = 0.0;
			for(i = 1;i <= n;i++)
			{
				m = i;
				for(j = i;j <= n;j++)
					if(Math.Abs(A[j,i]) > Math.Abs(A[m,i]))
						m = j;
				for(j = 1;j <= 2*n;j++)
				{
					temp = A[i,j];
					A[i,j] = A[m,j];
					A[m,j] = temp;
				}
				if(m != i)
					d = -d;
				if(A[i,i] == 0.0)
				{
					d = 0.0;
					return;
				}
				s = A[i,i];
				for(j = 1;j <= 2*n;j++)
					A[i,j] /= s;
				for(j = i + 1;j <= n;j++)
				{
					t = A[j,i];
					for(k = i;k <= 2*n;k++)
						A[j,k]-=A[i,k]*t;
				}
			}
			for(k = n + 1;k <= 2*n;k++)
			{
				for(i = n;i >= 1;i--)
				{
					s = A[i,k];
					for(j = i + 1;j <= n;j++)
						s -= A[i,j]*A[j,k];
					A[i,k] = s;
				}
			}
		}
	}
}