TicTacToeC#

using System.Runtime.InteropServices;

namespace TicTacToeFP;

public partial class TicTacToe
{

/*
************************************************************
    C# CONSOLE APPLICATION
    THIS PROJECT IS ABOUT A
    TIC TAC TOE GAME
    FOR THIS PROJECT IS USED FUNCTIONAL PROGRAMMING (FP)
************************************************************
*/

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

/*
************************************************************
                    START OF THE PROJECT
************************************************************
*/

/*
************************************************************
    THIS PART OF THE CODE IS TO MAKE
    THE CONSOLE WINDOW IN FULL SCREEN AUTOMATICALLY,
    WHEN CALLED
************************************************************
*/

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    [LibraryImport("kernel32.dll")]

    private static partial IntPtr GetConsoleWindow();

    private static readonly IntPtr ThisCon = GetConsoleWindow();

    [LibraryImport("user32.dll", SetLastError = true)]

    [return: MarshalAs(UnmanagedType.Bool)]

    private static partial bool ShowWindow(IntPtr hWnd, int nCmdShow);

    private const int MAXIMIZE = 3;

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

/*
************************************************************
    THIS PART OF THE CODE IS TO HELP
    THE "WriteCentered" METHOD TO CENTER THE TEXT
    IN THE MIDDLE OF THE CONSOLE
************************************************************
*/

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    [LibraryImport("kernel32.dll")]

    private static partial IntPtr GetStdHandle(int nStdHandle);

    [StructLayout(LayoutKind.Sequential)]

    struct COORD
    {
        public short X;

        public short Y;
    }

    [LibraryImport("kernel32.dll")]

    [return: MarshalAs(UnmanagedType.Bool)]

    private static partial bool GetConsoleScreenBufferInfo(IntPtr hConsoleOutput, out CONSOLE_SCREEN_BUFFER_INFO lpConsoleScreenBufferInfo);

    [StructLayout(LayoutKind.Sequential)]

    struct CONSOLE_SCREEN_BUFFER_INFO
    {
        public COORD dwSize;

        public COORD dwCursorPosition;

        public ushort wAttributes;

        public SMALL_RECT srWindow;

        public COORD dwMaximumWindowSize;
    }

    [StructLayout(LayoutKind.Sequential)]

    struct SMALL_RECT
    {
        public short Left;

        public short Top;

        public short Right;

        public short Bottom;
    }

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    static void Main(string[] args)
    {
        ShowWindow(ThisCon, MAXIMIZE); // FULL SCREEN

        Console.CursorVisible = false; // TURN THE VISIBILITY OF THE CURSOR TO OFF

        MainMenu();
    }

/*
************************************************************
    CREATING A METHOD,
    WHICH DOESN'T TAKE ANY PARAMETERS
    AND TAKES METHODS AS ELEMENTS,
    WHICH DON'T RETURN ANYTHING
************************************************************
*/

    delegate void menuOption();

/*
************************************************************
    USING THE CREATED METHOD TO CREATE AN ARRAY
************************************************************
*/

    static menuOption[] mainMenuOptions = { GameStart, ExitGame };

/*
************************************************************
    METHOD TO DISPLAY THE MAIN MENU
************************************************************
*/

    static void MainMenu()
    {
        string[] mainMenu = { "Start Game", "Exit" };

        int pointer = 0;

        bool arrowVisible = true;

        while (true)
        {
            Console.Clear();

            Console.ForegroundColor = ConsoleColor.Red;

            for (int i = 0; i < 16; i++)
            {
                Console.WriteLine();
            }

            WriteCentered("Tic Tac Toe");

            for (int i = 0; i < 3; i++)
            {
                Console.WriteLine();
            }

            WriteCentered("Main Menu");

            for (int i = 0; i < 3; i++)
            {
                Console.WriteLine();
            }

            for (int i = 0; i < mainMenu.Length; i++)
            {
                if (i == pointer)
                {
                    Console.ForegroundColor = ConsoleColor.Green;

                    if (arrowVisible)
                    {
                        WriteCentered("-> " + mainMenu[i]);

                        Console.WriteLine();

                        arrowVisible = false;
                    }

                    else
                    {
                        WriteCentered("   ");

                        Console.WriteLine();

                        arrowVisible = true;
                    }
                }

                else
                {
                    Console.ForegroundColor = ConsoleColor.Red;

                    WriteCentered(mainMenu[i]);

                    Console.WriteLine();
                }
            }

            if (Console.KeyAvailable)
            {
                ConsoleKeyInfo inputKey = Console.ReadKey(true);

                bool upKeyState = inputKey.Key == ConsoleKey.UpArrow;

                if (upKeyState)
                {
                    pointer--;

                    if (pointer == -1)
                    {
                        pointer = mainMenu.Length - 1;
                    }

                    continue;
                }

                bool downKeyState = inputKey.Key == ConsoleKey.DownArrow;

                if (downKeyState)
                {
                    pointer++;

                    if (pointer == mainMenu.Length)
                    {
                        pointer = 0;
                    }

                    continue;
                }

                bool returnKeyState = inputKey.Key == ConsoleKey.Enter;

                if (returnKeyState)
                {
                    mainMenuOptions[pointer]();
                }
            }

            Thread.Sleep(200);
        }
    }

/*
************************************************************
    METHOD TO CALL THE NEEDED METHODS,
    SO THE PLAYER / PLAYERS CAN PLAY
************************************************************
*/

    static void GameStart()
    {
        string[] names = new string [2];

        string choice = ChoiceMenu();

        if (choice == "yes")
        {
            char[] marks = { 'X', 'O' };

            Console.Clear();

            for (int i = 0; i < 20; i++)
            {
                Console.WriteLine();
            }

            for (int i = 0; i < names.Length; i++)
            {
                Console.WriteLine();

                WriteCentered("Enter a name for Player " + (i + 1).ToString() + ", who will be with the symbol '" + marks[i] + "': ");

                names[i] = EnterName();
            }
        }

        else if (choice == "no")
        {
            Console.ForegroundColor = ConsoleColor.Red;

            names[0] = "Player 1";

            names[1] = "Player 2";
        }

        GamePlay(names);
    }

/*
************************************************************
    METHOD TO EXIT THE GAME
************************************************************
*/

    static void ExitGame()
    {
        Console.Clear();

        Console.ForegroundColor = ConsoleColor.Red;

        Environment.Exit(0);
    }

/*
************************************************************
    CREATING A METHOD,
    WHICH DOESN'T TAKE ANY PARAMETERS
    AND TAKES METHODS AS ELEMENTS,
    WHICH RETURN A STRING
************************************************************
*/

    delegate string ChoiceOption();

/*
************************************************************
    USING THE CREATED METHOD TO CREATE AN ARRAY
************************************************************
*/

    static ChoiceOption[] choiceMenuOptions = { ChoiceIsYes, ChoiceIsNo };

/*
************************************************************
    METHOD TO DISPLAY THE CHOICE MENU
************************************************************
*/

    static string ChoiceMenu()
    {
        string[] choiceMenu = { "Yes", "No" };

        int pointer = 0;

        bool arrowVisible = true;

        while (true)
        {
            Console.Clear();

            Console.ForegroundColor = ConsoleColor.Red;

            for (int i = 0; i < 20; i++)
            {
                Console.WriteLine();
            }

            WriteCentered("Do you want to change the names from \"Player 1\" and \"Player 2\" to something different?");

            for (int i = 0; i < 3; i++)
            {
                Console.WriteLine();
            }

            for (int i = 0; i < choiceMenu.Length; i++)
            {
                if (i == pointer)
                {
                    Console.ForegroundColor = ConsoleColor.Green;

                    if (arrowVisible)
                    {
                        WriteCentered("-> " + choiceMenu[i]);

                        Console.WriteLine();

                        arrowVisible = false;
                    }

                    else
                    {
                        WriteCentered("   ");

                        Console.WriteLine();

                        arrowVisible = true;
                    }
                }

                else
                {
                    Console.ForegroundColor = ConsoleColor.Red;

                    WriteCentered(choiceMenu[i]);

                    Console.WriteLine();
                }
            }

            if (Console.KeyAvailable)
            {
                ConsoleKeyInfo inputKey = Console.ReadKey(true);

                bool upKeyState = inputKey.Key == ConsoleKey.UpArrow;

                if (upKeyState)
                {
                    pointer--;

                    if (pointer == -1)
                    {
                        pointer = choiceMenu.Length - 1;
                    }

                    continue;
                }

                bool downKeyState = inputKey.Key == ConsoleKey.DownArrow;

                if (downKeyState)
                {
                    pointer++;

                    if (pointer == choiceMenu.Length)
                    {
                        pointer = 0;
                    }

                    continue;
                }

                bool returnKeyState = inputKey.Key == ConsoleKey.Enter;

                if (returnKeyState)
                {
                    return choiceMenuOptions[pointer]();
                }

                BackToMainMenu(inputKey);
            }

            Thread.Sleep(200);
        }
    }

/*
************************************************************
    METHOD TO RETURN "yes",
    SO THE USER CAN INPUT DIFFERENT NAMES
************************************************************
*/

    static string ChoiceIsYes()
    {
        return "yes";
    }

/*
************************************************************
    METHOD TO RETURN "no",
    SO THE NAMES WON'T BE CHANGED
************************************************************
*/

    static string ChoiceIsNo()
    {
        return "no";
    }

/*
************************************************************
    METHOD TO INPUT A NAME
************************************************************
*/

    static string EnterName()
    {
        string name = Console.ReadLine();

        return name;
    }

/*
************************************************************
    METHOD TO ALLOW THE PLAYER / PLAYERS TO PLAY
************************************************************
*/

    static void GamePlay(string[] names)
    {
        string[] square = { "1", "2", "3", "4", "5", "6", "7", "8", "9" };

        int sizeOfTheArray = square.Length;

        int player = 1, gameState = -1;

        char mark;

        while ( (gameState == -1) && (player != 6) )
        {
            player = (player % 2 == 1) ? 1 : 2;

            mark = (player == 1) ? 'X' : 'O';

            Board(square, names, sizeOfTheArray);

            WriteCentered("It's " + names[player - 1] + "'s turn.");

            player = ActionChoice(square, player, mark, sizeOfTheArray);

            gameState = GameState(square);
        }

        if ( (gameState == 0) || (gameState == 1) )
        {
            Board(square, names, sizeOfTheArray);

            if (gameState == 1)
            {
                int index = (--player == 1) ? 0 : 1;

                WriteCentered("==> " + names[index] + " won! <==");
            }

            else if (gameState == 0)
            {
                WriteCentered("==> Game draw <==");
            }

            for (int i = 0; i < 2; i++)
            {
                Console.WriteLine();
            }

            PressEnterToContinue();
        }
    }

/*
************************************************************
    METHOD TO DRAW THE TIC TAC TOE BOARD
    WITH THE PLAYERS MARK
************************************************************
*/

    static void Board(string[] square, string[] names, int size)
    {
        Console.Clear();

        for (int i = 0; i < 14; i++)
        {
            Console.WriteLine();
        }

        WriteCentered("Tic Tac Toe");

        for (int i = 0; i < 4; i++)
        {
            Console.WriteLine();
        }

        WriteCentered(names[0] + " (X)  -  " + names[1] + " (O)");

        for (int i = 0; i < 4; i++)
        {
            Console.WriteLine();
        }

        WriteCentered("     |     |     ");

        Console.WriteLine();

        for (int i = 0; i < size - 2; i += 3)
        {
            WriteCentered(square[i] + "  |  " + square[i + 1] + "  |  " + square[i + 2]);

            Console.WriteLine();

            if (i != 6)
            {
                WriteCentered("_____|_____|_____");

                Console.WriteLine();

                WriteCentered("     |     |     ");

                Console.WriteLine();
            }
        }

        WriteCentered("     |     |     ");

        for (int i = 0; i < 4; i++)
        {
            Console.WriteLine();
        }
    }

/*
************************************************************
    METHOD TO ALLOW THE PLAYERS TO PRESS
     A NUMBER 1 TO 9 AND CHANGE IT TO EITHER 'X' OR 'O'
    "R" / "r" TO RESTART THE GAME
    "Q" / "q" TO GO BACK TO THE MAIN MENU
************************************************************
*/

    static int ActionChoice(string[] square, int player, char mark, int size)
    {
        while (true)
        {
            ConsoleKeyInfo inputKey = Console.ReadKey(true);

            int key = inputKey.KeyChar - '0';

            if ( ( (key > 0) && (key < 10) ) && (square[key - 1] == key.ToString()))
            {
                CheckActionChoice(square, mark, key, size);

                player++;

                break;
            }

            else if ( (inputKey.KeyChar == 'R') || (inputKey.KeyChar == 'r') ) // Check for 'R' or 'r' key press
            {
                for (int i = 0; i < size; i++)
                {
                    if ( (square[i] == "X") || (square[i] == "O") )
                    {
                        square[i] = (i + 1).ToString();
                    }
                }

                player = 1;

                break;
            }

            else if ( (inputKey.KeyChar == 'Q') || (inputKey.KeyChar == 'q') ) // Check for 'Q' or 'q' key press
            {
                player = 6; // It takes this value, so in the loop in the GamePlay function can break and go back to the Main Menu

                break;
            }

            else
            {
                Console.Clear();

                for (int i = 0; i < 20; i++)
                {
                    Console.WriteLine();
                }

                WriteCentered("Invalid move!");

                for (int i = 0; i < 4; i++)
                {
                    Console.WriteLine();
                }

                PressEnterToContinue();

                break;
            }
        }

        return player;
    }

/*
************************************************************
    METHOD TO CHECK THE PRESSED NUMBER,
       IF IT CAN BE CHANGED TO EITHER
                 'X' OT 'O'
************************************************************
*/

    static void CheckActionChoice(string[] square, char mark, int key, int size)
    {
        for (int i = 0; i < size; i++)
        {
            if (key.ToString() == square[i])
            {
                square[i] = mark.ToString();

                break;
            }
        }
    }

/*
************************************************************
    METHOD TO RETURN THE GAME STATUS:
     1 ==> GAME IS OVER WITH A RESULT
    -1 ==> GAME IS IN PROGRESS
     O ==> GAME IS OVER AND NO RESULT
************************************************************
*/

    static int GameState(string[] square)
    {
        if ( (square[0] == square[1]) && (square[1] == square[2]) )
        {
            return 1;
        }

        else if ( (square[3] == square[4]) && (square[4] == square[5]) )
        {
            return 1;
        }

        else if ( (square[6] == square[7]) && (square[7] == square[8]) )
        {
            return 1;
        }

        else if ( (square[0] == square[3]) && (square[3] == square[6]) )
        {
            return 1;
        }

        else if ( (square[1] == square[4]) && (square[4] == square[7]) )
        {
            return 1;
        }

        else if ( (square[2] == square[5]) && (square[5] == square[8]) )
        {
            return 1;
        }

        else if ( (square[0] == square[4]) && (square[4] == square[8]) )
        {
            return 1;
        }

        else if ( (square[2] == square[4]) && (square[4] == square[6]) )
        {
            return 1;
        }

        else if ( (square[0] != "1") && (square[1] != "2") && (square[2] != "3") &&
                  (square[3] != "4") && (square[4] != "5") && (square[5] != "6") &&
                  (square[6] != "7") && (square[7] != "8") && (square[8] != "9") )
        {
            return 0;
        }

        return -1;
    }

/*
************************************************************
    METHOD TO ALLOW THE USER
    TO GO BACK TO THE MAIN MENU,
    IF THE "ESCAPE" BUTTON IS PRESSED
************************************************************
*/

    static void BackToMainMenu(ConsoleKeyInfo inputKey)
    {
        if (inputKey.Key == ConsoleKey.Escape)
        {
            MainMenu();
        }
    }

/*
************************************************************
    METHOD TO ALLOW THE USER TO INPUT AGAIN,
    IF THE "ENTER" BUTTON IS PRESSED
************************************************************
*/

    static void PressEnterToContinue()
    {
        WriteCentered("Press \"ENTER\" to continue!");

        while (Console.ReadKey(true).Key != ConsoleKey.Enter);
    }

/*
************************************************************
    METHOD TO CENTER THE TEXT
    IN THE MIDDLE OF THE CONSOLE
************************************************************
*/

    static void WriteCentered(string text)
    {

        int consoleWidth = Console.WindowWidth;

        int textWidth = text.Length;

        int leftMargin = (consoleWidth - textWidth) / 2;

        string centeredText = new string(' ', leftMargin) + text;

        Console.Write(centeredText);
    }

/*
************************************************************
                     END OF THE PROJECT
************************************************************
*/

////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

}