Connect4 Game

How this game is playe can be found at here.

Python

ROWS = 6
COLS = 7

def create_board():
    return [[' ' for _ in range(COLS)] for _ in range(ROWS)]

def print_board(board):
    for row in board:
        print('|'.join(row))
    print('-' * (2 * COLS - 1))
    print(' '.join(map(str, range(COLS))))

def drop_token(board, col, token):
    for row in reversed(range(ROWS)):
        if board[row][col] == ' ':
            board[row][col] = token
            return row, col
    return None  # Column is full

def check_winner(board, row, col, token):
    def count_direction(dr, dc):
        r, c = row + dr, col + dc
        count = 0
        while 0 <= r < ROWS and 0 <= c < COLS and board[r][c] == token:
            count += 1
            r += dr
            c += dc
        return count

    directions = [ (0, 1), (1, 0), (1, 1), (1, -1) ]
    for dr, dc in directions:
        count = 1 + count_direction(dr, dc) + count_direction(-dr, -dc)
        if count >= 4:
            return True
    return False

if __name__ == "__main__":
    board = create_board()
    current_player = 0
    tokens = ['X', 'O']

    while True:
        print_board(board)
        
        while True:
            try:
                col = int(input(f"Player {current_player + 1} ({tokens[current_player]}), choose column (0-{COLS-1}): "))
                if col < 0 or col >= COLS:
                    print("Invalid column. Please choose a number between 0 and 6.")
                    continue
                result = drop_token(board, col, tokens[current_player])
                if result is None:
                    print(f"Column {col} is full. Try another one.")
                    continue
                else:
                    row, col = result
                    break
            except ValueError:
                print("Please enter a valid integer.")

        if check_winner(board, row, col, tokens[current_player]):
            print_board(board)
            print(f"Player {current_player + 1} ({tokens[current_player]}) wins!")
            break

        current_player = 1 - current_player

 

Java

public class Connect4 {
    char[][] board = new char[6][7];

    public Connect4(char[][] board) {
        this.board = board;
    }

    public static void main(String[] args) {
        Connect4 game = new Connect4(new char[6][7]);
        game.fillBoard(' ');
        Scanner input = new Scanner(System.in);
        char player = 'X';
        while (true) {
            game.showGameBoard();
            System.out.print("Player " + player + ", please enter the column where you'd like to drop your piece: ");
            int col = input.nextInt();
            if (game.tryDropPiece(col, player)) {
                if (game.checkForWin()) {
                    System.out.println("Player " + player + " wins!");
                    game.showGameBoard();
                    return;
                }
                player = game.switchPlayer(player); // Switch players
            }
        }
    }

    public char[][] fillBoard(char myChar) {
        for (int row = 0; row < board.length; row++) {
            Arrays.fill(board[row], 0, board[row].length, myChar);
        }
        return board;
    }

    public void showGameBoard() {
        System.out.println();
        for (int row = 0; row < board.length; row++) {
            System.out.print("|");
            for (int col = 0; col < board[row].length; col++) {
                System.out.print(" " + board[row][col] + " |");
            }
            System.out.println();
        }
    }

    public boolean tryDropPiece(int col, char player) {
        if (board[0][col] != ' ') {
            System.out.println("That column is already full.");
            return false;
        }
        for (int row = board.length - 1; row >= 0; row--) {
            if (board[row][col] == ' ') {
                board[row][col] = player;
                return true;
            }
        }
        return false;
    }

    public boolean checkForWin() {
        boolean result = false;
        // Check for win horizontally
        for (int row = 0; row < board.length; row++) {
            for (int col = 0; col < board[row].length - 3; col++) {
                if (board[row][col] != ' ' && board[row][col] == board[row][col + 1]
                        && board[row][col] == board[row][col + 2] && board[row][col] == board[row][col + 3]) {
                    return true;
                }
            }
        }
        // Check for win vertically
        for (int col = 0; col < board[0].length; col++) {
            for (int row = 0; row < board.length - 3; row++) {
                if (board[row][col] != ' ' && board[row][col] == board[row + 1][col]
                        && board[row][col] == board[row + 2][col] && board[row][col] == board[row + 3][col]) {
                    return true;
                }
            }
        }

        // Check for win diagonally, from top left
        for (int row = 0; row < board.length - 3; row++) {
            for (int col = 0; col < board[row].length - 3; col++) {
                if (board[row][col] != ' ' && board[row][col] == board[row + 1][col + 1]
                        && board[row][col] == board[row + 2][col + 2] && board[row][col] == board[row + 3][col + 3]) {
                    return true;
                }
            }
        }

        // Check for win diagonally, from top right
        for (int row = 0; row < board.length - 3; row++) {
            for (int col = 3; col < board[row].length; col++) {
                if (board[row][col] != ' ' && board[row][col] == board[row + 1][col - 1]
                        && board[row][col] == board[row + 2][col - 2] && board[row][col] == board[row + 3][col - 3]) {
                    return true;
                }
            }
        }
        return false;

    }

    public char switchPlayer(char currentPlayer) {
        if (currentPlayer == 'X') {
            return 'O';
        } else {
            return 'X';
        }
    }
}