This is an Object Oriented rewrite of my already rewritten Dart battleship game. I wanted to see how some of the OOP magic features worked. Very nice. Original, more functional approach: https://gist.github.com/Rican7/7480097

oop-improved-dart-version-of-codecademy-battleship.dart

import "dart:math";
import "dart:io";

/// Represent a mark on a board
class Mark extends Point<int> {
    // Properties

    bool _checked = false;
    String _representation;


    // Methods

    /// Constructor
    Mark(x, y, [_representation = "O"]) : super(x, y) {
        this.representation = _representation;
    }

    // Setters
    set representation(String value) => _representation = value.substring(0, 1).toUpperCase();
    set checked(bool value) {
        _checked = value;
        _representation = "X";
    }

    // Getters
    String get representation => _representation;
    bool get checked => _checked;

    /// String representation
    String toString() {
        return _representation;
    }
}

/// Represents a game board
class Board {
    // Properties

    final int numOfRows, numOfCols;
    List<List> board;


    // Methods

    /// Constructor
    Board([this.numOfRows = 5, this.numOfCols = 5]) {
        // Setup our board by filling it with [numOfRows] rows
        this.board = new List<List>.generate(numOfRows, (rowIndex) {
            // Create a list with a [numOfCols] of Marks
            return new List<Mark>.generate(numOfCols, (colIndex) {
                return new Mark(colIndex, rowIndex);
            });
        });
    }

    /// Get a mark on the board based on a Point
    Mark getMarkByPoint(Point<int> point) {
        return board[point.y][point.x];
    }

    /// String representation
    String toString() {
        var string = "\n";

        for (var row in board) {
            string += row.join(" ") + "\n";
        }

        return string;
    }
}

class Game {
    // Properties

    final int numOfTurns;


    // Methods

    /// Constructor
    Game([this.numOfTurns = 4]);

    /// Create random hidden ship for a given board
    Point<int> createHiddenShip(Board board) {
        // Generate a new randomizer
        var randomizer = new Random();

        return new Point(
            randomizer.nextInt(board.numOfCols),
            randomizer.nextInt(board.numOfRows)
        );
    }

    /// Print an introduction
    void printIntroduction() {
        print("Let's play Battleship!");
    }

    /// Get the user's guess as a Point
    Point<int> getGuessPoint() {
        // Get the guess row
        print("Guess row: ");
        var guessRow = int.parse(stdin.readLineSync());

        // Get the guess col
        print("Guess col: ");
        var guessCol = int.parse(stdin.readLineSync());

        print("");

        // Create a point from their guess values
        return new Point(guessCol, guessRow);
    }

    bool checkGuess(Board gameBoard, Point<int> hiddenShip, Point<int> guessPoint) {
        if (hiddenShip == guessPoint) {
            print("Congratulations! You sunk my battleship!");
            return true;

        } else {
            if ((guessPoint.x < 0 || guessPoint.x > gameBoard.numOfCols) ||
                (guessPoint.y < 0 || guessPoint.y > gameBoard.numOfRows)) {

                print("Oops, that's not even in the ocean.");

            } else if (gameBoard.getMarkByPoint(guessPoint).checked) {
                print("You guessed that one already.");

            } else {
                print("You missed my battleship!");
                gameBoard.getMarkByPoint(guessPoint).checked = true;
            }
        }

        return false;
    }

    /// Play the game
    void play({Board gameBoard}) {
        // Initialize
        gameBoard = null != gameBoard ? gameBoard : new Board();

        // Hide the ship
        var hiddenShip = createHiddenShip(gameBoard);

        // Introduce them
        printIntroduction();

        for (var turn = 0; turn < numOfTurns; turn++) {
            print(gameBoard);

            var guessPoint = getGuessPoint();

            // Check the guess' accuracy
            var result = checkGuess(gameBoard, hiddenShip, guessPoint);

            if (result) {
                break;
            }

            print("Finished turn ${turn + 1}");
        }

        print("Game Over");
    }
}

void main(args) {
    new Game().play();
}