wczytywanie z pliku i wypisywanie

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

namespace mozesieuda
{
    public static class FilesStream
    {
        public static char[,] map = null;
        public static Treenode mainnode = null;
        public static LinkedList<Treenode> list;
        public static int rows, columns;
        public static int counter=0;
        public static void GetInput()
        {
            rows = 0;
            columns = 0;
            map = null;
            int z = 0;
            try
            {
                using (StreamReader str = new StreamReader("in3.txt"))
                {
                    string line = "";
                    while ((line = str.ReadLine()) != null)
                    {
                        if (line.Length == columns)
                        {
                            for (int i = 0; i < columns; i++)
                            {
                                map[z, i] = line[i];
                                if(line[i]=='x' && z!=0&& z!=rows-1 && i!=0 && i!=columns-1)
                                {
                                    list.AddLast(new Treenode {currentrow=z,currentcolumn=i});
                                }
                            }
                            z++;
                        }
                        else
                        {
                            var split = line.Split(' ');
                            list = new LinkedList<Treenode>();
                            int.TryParse(split[0], out rows);
                            int.TryParse(split[1], out columns);
                            map = new char[rows, columns];

                        }
                    }
                }
            }
            catch (IOException)
            {
                Console.WriteLine("File not found");
                throw;
            }

        }
        public static void Output(int? island, int? river)
        {
            using (StreamWriter stw = new StreamWriter("out3.txt"))
            {
                stw.Write(island + " " + river);
            }
        }
    }

}