public static char[,] MakeMove(char[,] boardMatrix, int size)
 {
     // loop through all board positions until valid move is found
     for (int xcoord = 0; xcoord < size; xcoord++)
     {
         for (int ycoord = 0; ycoord < size; ycoord++)
         {
             // look left
             for (int x = xcoord; x > 0; x--)
             {
                 // look all positions to left for friendly char
                 if (boardMatrix[x, ycoord] == 'O')
                 {
                     // look 1 position to left for opposing char
                     if (boardMatrix[xcoord - 1, ycoord] == 'X')
                     {
                         int xstop = x;
                         // change positions
                         for (int j = xcoord; j > xstop; j--)
                         {
                             boardMatrix[j, ycoord] = 'O';
                         }
                         Console.WriteLine("Computer entered a move at {0}{1}", xcoord, ycoord);
                         return(boardMatrix);
                     }
                 }
             }
             // look right
             for (int x = xcoord; x < Math.Sqrt(boardMatrix.Length); x++)
             {
                 // look all positions to the right for friendly char
                 if (boardMatrix[x, ycoord] == 'O')
                 {
                     // look 1 position to the right for opposing char
                     if (boardMatrix[xcoord + 1, ycoord] == 'X')
                     {
                         int xstop = x;
                         // change positions
                         for (int j = xcoord; j < xstop; j++)
                         {
                             boardMatrix[j, ycoord] = 'O';
                         }
                         Console.WriteLine("Computer entered a move at {0}{1}", xcoord, ycoord);
                         return(boardMatrix);
                     }
                 }
             }
             // look up
             for (int y = ycoord; y >= 0; y--)
             {
                 // look all positions up for friendly char
                 if (boardMatrix[xcoord, y] == 'O')
                 {
                     // look 1 position up for opposing char
                     if (boardMatrix[xcoord, ycoord - 1] == 'X')
                     {
                         int ystop = y;
                         // change positions
                         for (int j = ycoord; j > ystop; j--)
                         {
                             boardMatrix[xcoord, j] = 'O';
                         }
                         Console.WriteLine("Computer entered a move at {0}{1}", xcoord, ycoord);
                         return(boardMatrix);
                     }
                 }
             }
             // look down
             for (int y = ycoord; y < Math.Sqrt(boardMatrix.Length); y++)
             {
                 // look all positions below for friendly char
                 if (boardMatrix[xcoord, y] == 'O')
                 {
                     // look 1 position below for opposing char
                     if (boardMatrix[xcoord, ycoord + 1] == 'X')
                     {
                         int ystop = y;
                         // change positions
                         for (int j = ycoord; j < ystop; j++)
                         {
                             boardMatrix[xcoord, j] = 'O';
                         }
                         Console.WriteLine("Computer entered a move at {0}{1}", xcoord, ycoord);
                         return(boardMatrix);
                     }
                 }
             }
         }
     }
     // else end game
     EndOfGame.Score(boardMatrix);
     return(boardMatrix);
 }
        public static void TurnLoop(string mode, int size, char[,] boardMatrix)
        {
            // set player char arrays for looping though
            char[] activeplayer = new char[] { 'X', 'O' };
            char[] idleplayer   = new char[] { 'O', 'X' };
            int[]  playerid     = new int[] { 1, 2 };
            bool   gameover     = false;

            // loop for 2 human players
            if (mode == "h1")
            {
                while (gameover == false)
                {
                    for (int i = 0; i < 2; i++)
                    {
                        // render board map
                        Board.DrawMap(size);
                        // render in board state
                        Console.WriteLine("\n");
                        for (int y = 0; y < size; y++)
                        {
                            for (int x = 0; x < size; x++)
                            {
                                Console.Write(string.Format("|{0}", boardMatrix[x, y]));
                                if (x == size - 1)
                                {
                                    Console.Write("|\n");
                                }
                            }
                        }
                        // prompt and handle user input
                        Console.WriteLine("\nPlayer {0}, your pieces are denoted by '{1}'. Enter a 2 digit co-ordinate to place, 'help' to view rules again, 'save' to save the current board state and 'end' to view the current score and finish:", playerid[i], activeplayer[i]);
                        string req   = Console.ReadLine();
                        bool   input = Int32.TryParse(req, out int placing);
                        // print game rules
                        if (req == "help")
                        {
                            Help.PrintHelp(size);
                        }
                        // save board matrix to txt file
                        else if (req == "save")
                        {
                            using (StreamWriter sr = new StreamWriter("save.txt"))
                            {
                                foreach (var item in boardMatrix)
                                {
                                    sr.WriteLine(item);
                                }
                            }
                            Console.WriteLine("The game has been saved to save.txt.");
                        }
                        // end game - display score
                        else if (req == "end")
                        {
                            EndOfGame.Score(boardMatrix);
                        }
                        // action move request if valid number input
                        else if (input)
                        {
                            int xcoord = placing / 10;
                            int ycoord = placing % 10;
                            boardMatrix = HumanMove.LookAndPlace(xcoord, ycoord, boardMatrix, activeplayer[i], idleplayer[i]);
                            // end of game test
                            int count = 0;
                            foreach (char square in boardMatrix)
                            {
                                if (square == ' ')
                                {
                                    count++;
                                }
                            }
                            if (count == 0)
                            {
                                EndOfGame.Score(boardMatrix);
                            }
                        }
                        else
                        {
                            Console.Write("\nInput not recognised.");
                        }
                    }
                }
            }
            // loop for 1 computer player, 1 human
            else if (mode == "c1")
            {
                while (gameover == false)
                {
                    for (int i = 0; i < 2; i++)
                    {
                        // render in board state console
                        Console.WriteLine("\n");
                        for (int y = 0; y < size; y++)
                        {
                            for (int x = 0; x < size; x++)
                            {
                                Console.Write(string.Format("|{0}", boardMatrix[x, y]));
                                if (x == size - 1)
                                {
                                    Console.Write("|\n");
                                }
                            }
                        }
                        // prompt and handle human input
                        Console.WriteLine("\nPlayer 1, your pieces are denoted by 'X'. Enter a 2 digit co-ordinate to place, 'help' to view rules again, 'save' to save the current board state and 'end' to view the current score and finish:");
                        string req   = Console.ReadLine();
                        bool   input = Int32.TryParse(req, out int placing);
                        // print game rules
                        if (req == "help")
                        {
                            Help.PrintHelp(size);
                        }
                        // save board state to txt file
                        else if (req == "save")
                        {
                            using (StreamWriter sr = new StreamWriter("save.txt"))
                            {
                                foreach (var item in boardMatrix)
                                {
                                    sr.WriteLine(item);
                                }
                            }
                            Console.WriteLine("The game has been saved to save.txt.");
                        }
                        // end game - show scores
                        else if (req == "end")
                        {
                            EndOfGame.Score(boardMatrix);
                        }
                        // action move request if valid number input
                        else if (input)
                        {
                            int xcoord = placing / 10;
                            int ycoord = placing % 10;
                            boardMatrix = HumanMove.LookAndPlace(xcoord, ycoord, boardMatrix, 'X', 'O');
                        }
                        else
                        {
                            Console.Write("\nInput not recognised.");
                        }
                        // computer move
                        boardMatrix = EasyAI.MakeMove(boardMatrix, size);
                        // test for full board, if so end game
                        foreach (char square in boardMatrix)
                        {
                            if (square == ' ')
                            {
                                break;
                            }
                            else
                            {
                                EndOfGame.Score(boardMatrix);
                            }
                        }
                    }
                }
            }
        }