# Coding a game of tic-tac-toe using 3 different languages

I used a brute force logic to develop an algorithm for tic-tac-toe.
Firstly, there are only 8 triads of winning points or moves: three vertical, three horizontal and 2 diagonals.
Players play taking turns or making moves alternately. Player 1 makes a maximum of 5 moves and player
2 makes a maximum of 4 moves because there are a maximum of 9 moves to be made and player 1 begins the game.

Furthermore, player 1 has already made 2 moves before getting his first chance to form a winning line.
Players take turns alternately which means that when player 1 gets his first chance to form a line,
player 2 has already made 2 moves of his own. So player 1 can only form a line from move 5. Player 2
can only form his first line at move 6. Player 1 gets his second chance to win at move 7 and his third
and last chance at move 9. Similarly, player 2 gets his second and last chance at move 8.

Every time there is a chance to form a winning line, all possible permutations and combinations of
the current players moves, taken three at a time, are compared with all 8 winning triads. If a match is found,
the current player wins. If player 1 forms a line first, player 2 does not get a chance to continue the game.

The game has 3 versions: PHP, Java and C#

### PHP Version

It can be played via the command-line executable of your PHP installation.

In the game of tic-tac-toe there is a 3X3 grid or board.The game is for two players. The players 1 and 2 take turns to mark the cells of the grid with their mark which is a zero or a cross.

The first player to complete a vertical, horizontal or diagonal triad of zeroes or crosses, wins.

In this implementation, I have used the OOPs or Object Oriented Programming features of PHP.

I have divided the functionality and roles or responsibilities between various classes as follows.

Player makes Move on Board to play Game. So the classes are:

1. Move
2. Board
3. Player
4. Game

First we discuss the move class:

### Move:

Move made by either of the players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 class Move { private \$row; // between 1 and 3 private \$column; //between 1 and 3 on the 3x3 board private \$isValid; //whether the move is valid or not   //getters and setters for the properties public function setRow(\$i) { \$this->row = \$i; }   public function setColumn(\$j) { \$this->column = \$j; }   public function setValid(\$valid) { \$this->isValid = \$valid; }   public function getRow() { return \$this->row; }   public function getColumn() { return \$this->column; }   public function getValid() { return \$this->isValid; } }```

Then comes the Board class where the moves are made.

### Board:

The board on which the game is played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 class Board { private \$cells = array(); //the 3x3 grid of cells   public function __construct() { \$row1 = array(" ", " ", " ");   \$row2 = array(" ", " ", " ");   \$row3 = array(" ", " ", " ");   \$this->cells[0] = \$row1;   \$this->cells[1] = \$row2;   \$this->cells[2] = \$row3; }   //display the board with moves made so far public function display() { for(\$i = 0; \$i < 3; \$i++) { for(\$j = 0; \$j < 3; \$j++) { if(\$this->cells[\$i][\$j] == " ") { echo (\$i + 1).", ".(\$j + 1)."\t"; } else { echo \$this->cells[\$i][\$j]."\t"; } }   echo "\n\n"; } }   //check if a cell is already occupied or not public function checkAvailable(\$move) { \$i = \$move->getRow(); \$j = \$move->getColumn();   \$valid1 = ((\$i >= 1 && \$i <= 3) && (\$j >= 1 && \$j <= 3));   if(\$valid1) { \$valid2 = (\$this->cells[\$i - 1][\$j - 1] == " "); } else { \$valid2 = false; }   \$valid3 = (\$valid1 && \$valid2);   \$move->setValid(\$valid3);   return \$move; }   //put a cross or zero in a cell if the move is valid public function markCell(\$move, \$mark) { if(\$move->getValid()) { \$i = \$move->getRow(); \$j = \$move->getColumn();   \$this->cells[\$i - 1][\$j - 1] = \$mark; } else { echo "INVALID MOVE!\n\n"; } } }```

The Player class denotes the players who make moves on the board.

### Player:

Either of the two players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 class Player { private \$playerNum; //player 1 or 2 private \$playerMark; // '0' or 'X' private \$winnerOrLoser; private \$moves = array(); //list of moves made by player private \$g; //the game being played   //getters and setters public function setPlayerNum(\$num) { \$this->playerNum = \$num; }   public function setPlayerMark(\$mark) { \$this->playerMark = \$mark; }   public function setPlayerWinnerLoser(\$winnerOrLoser) { \$this->winnerOrLoser = \$winnerOrLoser; }   public function getPlayerNum() { return \$this->playerNum; }   public function getPlayerMark() { return \$this->playerMark; }   public function getPlayerWinLose() { return \$this->winnerOrLoser; }   public function getPlayerMoves() { return \$this->moves; }   //the player can put x or 0 by choosing the cell (row and column) public function makeMove(\$board, \$move) { \$move = \$board->checkAvailable(\$move);   \$mark = \$this->getPlayerMark(); \$board->markCell(\$move, \$mark);   if(\$move->getValid()) { \$this->addMove(\$move);   \$this->getGame()->setMovesTillNow(); }   \$board->display(); }   //if move is valid, add the move to the player's list of moves public function addMove(\$move) { \$this->moves[] = \$move; }   public function setGame(\$game) { \$this->g = \$game;   }   public function getGame() { return \$this->g; } }```

The Game class is the functionality of the game with all its rules.

### Game:

The game being played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 class Game { private \$whoseTurn; //player 1 or 2 private static \$movesTillNow = 0; //how many moves till now private \$gameOver; //is game over yet? private \$winningMoves; //list of combination of moves which can win the game private \$winner = null;   private \$winning_moves;   public function __construct() { //winning moves   \$this->winning_moves = array(); //row wise   \$move01 = new Move(); \$move01->setRow(1); \$move01->setColumn(1);   \$move02 = new Move(); \$move02->setRow(1); \$move02->setColumn(2);   \$move03 = new Move(); \$move03->setRow(1); \$move03->setColumn(3);   \$move0 = array(\$move01, \$move02, \$move03);   \$this->winning_moves[0] = \$move0;   \$move11 = new Move(); \$move11->setRow(2); \$move11->setColumn(1);   \$move12 = new Move(); \$move12->setRow(2); \$move12->setColumn(2);   \$move13 = new Move(); \$move13->setRow(2); \$move13->setColumn(3);   \$move1 = array(\$move11, \$move12, \$move13);   \$this->winning_moves[1] = \$move1;   \$move21 = new Move(); \$move21->setRow(3); \$move21->setColumn(1);   \$move22 = new Move(); \$move22->setRow(3); \$move22->setColumn(2);   \$move23 = new Move(); \$move23->setRow(3); \$move23->setColumn(3);     \$move2 = array(\$move21, \$move22, \$move23);   \$this->winning_moves[2] = \$move2;   //column wise   \$move31 = new Move(); \$move31->setRow(1); \$move31->setColumn(1);   \$move32 = new Move(); \$move32->setRow(2); \$move32->setColumn(1);   \$move33 = new Move(); \$move33->setRow(3); \$move33->setColumn(1);   \$move3 = array(\$move31, \$move32, \$move33);   \$this->winning_moves[3] = \$move3;   \$move41 = new Move(); \$move41->setRow(1); \$move41->setColumn(2);   \$move42 = new Move(); \$move42->setRow(2); \$move42->setColumn(2);   \$move43 = new Move(); \$move43->setRow(3); \$move43->setColumn(2);   \$move4 = array(\$move41, \$move42, \$move43);   \$this->winning_moves[4] = \$move4;   \$move51 = new Move(); \$move51->setRow(1); \$move51->setColumn(3);   \$move52 = new Move(); \$move52->setRow(2); \$move52->setColumn(3);   \$move53 = new Move(); \$move53->setRow(3); \$move53->setColumn(3);   \$move5 = array(\$move51, \$move52, \$move53);   \$this->winning_moves[5] = \$move5;   //diagonally   \$move61 = new Move(); \$move61->setRow(1); \$move61->setColumn(1);   \$move62 = new Move(); \$move62->setRow(2); \$move62->setColumn(2);   \$move63 = new Move(); \$move63->setRow(3); \$move63->setColumn(3);   \$move6 = array(\$move61, \$move62, \$move63);   \$this->winning_moves[6] = \$move6;   \$move71 = new Move(); \$move71->setRow(1); \$move71->setColumn(3);   \$move72 = new Move(); \$move72->setRow(2); \$move72->setColumn(2);   \$move73 = new Move(); \$move73->setRow(3); \$move73->setColumn(1);   \$move7 = array(\$move71, \$move72, \$move73);   \$this->winning_moves[7] = \$move7; }   //getters and setters public function getWhoseTurn() { return \$this->whoseTurn; }   public function setWhoseTurn(\$player) { \$this->whoseTurn = \$player->getPlayerNum(); }   public function getGameOver() { return \$this->gameOver; }   public function setGameOver(\$gameOver) { \$this->gameOver = \$gameOver; }   public function setMovesTillNow() { self::\$movesTillNow++; }   public function getMovesTillNow() { return self::\$movesTillNow; }   public function setWinner(\$winner) { \$this->winner = \$winner; }   public function getWinner() { return \$this->winner; }   //check if winning moves have been made by either player public function checkWinningMoves(\$player) {   \$movesTillNow = \$this->getMovesTillNow();   \$whoseTurn = \$this->getWhoseTurn();   \$playerMoves = \$player->getPlayerMoves();   \$moves = \$movesTillNow;   \$winning_moves1 = \$this->winning_moves;   switch(\$whoseTurn) { case 1:   if(\$moves < 5) { return false; } else {   if(\$moves == 5) {   \$player1_set1 = array(\$playerMoves[0], \$playerMoves[1], \$playerMoves[2]);   for(\$i = 0; \$i < 8; \$i++) { if(\$this->checkSubset(\$player1_set1, \$winning_moves1[\$i])) { return true; } }   }   if(\$moves == 7) { \$player1_set2 = array(\$playerMoves[0], \$playerMoves[1], \$playerMoves[3]);   \$player1_set4 = array(\$playerMoves[0], \$playerMoves[2], \$playerMoves[3]);   \$player1_set7 = array(\$playerMoves[1], \$playerMoves[2], \$playerMoves[3]);   for(\$i = 0; \$i < 8; \$i++) { if(\$this->checkSubset(\$player1_set2, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set4, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set7, \$winning_moves1[\$i]) ) { return true; } } }   if(\$moves == 9) {   \$player1_set3 = array(\$playerMoves[0], \$playerMoves[1], \$playerMoves[4]);   \$player1_set5 = array(\$playerMoves[0], \$playerMoves[2], \$playerMoves[4]);   \$player1_set6 = array(\$playerMoves[0], \$playerMoves[3], \$playerMoves[4]);   \$player1_set8 = array(\$playerMoves[1], \$playerMoves[2], \$playerMoves[4]);   \$player1_set9 = array(\$playerMoves[1], \$playerMoves[3], \$playerMoves[4]);   \$player1_set10 = array(\$playerMoves[2], \$playerMoves[3], \$playerMoves[4]);   for(\$i = 0; \$i < 8; \$i++) { if(\$this->checkSubset(\$player1_set3, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set5, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set6, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set8, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set9, \$winning_moves1[\$i]) || \$this->checkSubset(\$player1_set10, \$winning_moves1[\$i])) { return true; } }   }   return false;       } break; case 2: if(\$moves < 6) { return false; } else { if(\$moves == 6) { \$player2_set1 = array(\$playerMoves[0], \$playerMoves[1], \$playerMoves[2]);   for(\$i = 0; \$i < 8; \$i++) { if(\$this->checkSubset(\$player2_set1, \$winning_moves1[\$i])) { return true; } } }   if(\$moves == 8) {   \$player2_set2 = array(\$playerMoves[0], \$playerMoves[1], \$playerMoves[3]);   \$player2_set3 = array(\$playerMoves[0], \$playerMoves[2], \$playerMoves[3]);   \$player2_set4 = array(\$playerMoves[1], \$playerMoves[2], \$playerMoves[3]);   for(\$i = 0; \$i < 8; \$i++) { if(\$this->checkSubset(\$player2_set2, \$winning_moves1[\$i]) || \$this->checkSubset(\$player2_set3, \$winning_moves1[\$i]) || \$this->checkSubset(\$player2_set4, \$winning_moves1[\$i])) { return true; } } }       return false;   } break; default: return false; }     }   //check if player moves match the winning sequence private function checkSubset(\$subset, \$winning_row) {   \$count = 0; for(\$i = 0; \$i < 3; \$i++) {   for(\$j = 0; \$j < 3; \$j++) { if(\$subset[\$i]->getRow() == \$winning_row[\$j]->getRow() && \$subset[\$i]->getColumn() == \$winning_row[\$j]->getColumn()) { \$count++; } }   } return (\$count == 3);   } }```

### Putting it all together.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139   require("includes/move.php"); //the Move class   require("includes/player.php"); //the Player class   require("includes/board.php"); //the Board class   require("includes/game.php"); //the Game class   function main() //where all the action is { \$game = new Game();   \$player1 = new Player();   \$player1->setPlayerNum(1);   \$player1->setPlayerMark('X');   \$player1->setGame(\$game);   \$player2 = new Player();   \$player2->setPlayerNum(2);   \$player2->setPlayerMark('0');   \$player2->setGame(\$game);   \$b = new Board();   \$b->display();   \$game->setWhoseTurn(\$player1);   \$game->setGameOver(false);   \$status = \$game->getGameOver();   do { \$movesNow = \$game->getMovesTillNow();   if(\$movesNow == 9) {   if(\$game->getWinner() == null) { echo "TIE!"; break; }   }   \$turn = \$game->getWhoseTurn();   echo "PLAYER \$turn:\n\n";   \$row = 0; \$column = 0;   echo "Enter row: ";   trim(fscanf(STDIN, "%d\n", \$row));   echo "Enter column: ";   trim(fscanf(STDIN, "%d\n", \$column));   echo "\n";   \$move = new Move();   \$move->setRow(\$row);   \$move->setColumn(\$column);   switch(\$turn) { case 1: \$player1->makeMove(\$b, \$move);   if(\$game->checkWinningMoves(\$player1)) {   \$game->setWinner(\$player1);   echo "PLAYER 1 WINS!\n\n";   \$game->setGameOver(true); } else { if(\$move->getValid()) { \$movesNow = \$game->getMovesTillNow();   echo "MOVE NUMBER: \$movesNow\n\n";   \$game->setWhoseTurn(\$player2);   } } break; case 2: \$player2->makeMove(\$b, \$move);   if(\$game->checkWinningMoves(\$player2)) {   \$game->setWinner(\$player2);   echo "PLAYER 2 WINS!\n\n";   \$game->setGameOver(true); } else { if(\$move->getValid()) { \$movesNow = \$game->getMovesTillNow();   echo "MOVE NUMBER: \$movesNow\n\n";   \$game->setWhoseTurn(\$player1); } } break; default: echo "ERROR!\n\n"; break; }   \$status = \$game->getGameOver();   }while(!\$status);   }   main(); //invoking the game play```

This implementation is not perfect by any means. Any suggestions for improvement are welcome. Screenshots given below:

### Java Version

Here is an elementary tic-tac-toe or noughts and crosses game made in Java.
It can be played via the java interpreter from the command line. In the game of tic-tac-toe there is a 3X3 grid or board.The game is for two players. The players take turns to mark the cells of the grid with their mark which is a zero or a cross.

The first player to complete a vertical, horizontal or diagonal triad of zeroes or crosses, wins.

The PHP version can be found here

Player makes Move on Board to play Game. So the classes are:

1. Move
2. Board
3. Player
4. Game
5. TicTacToe

There is one new class “TicTacToe” because Java needs a main class having the “main” method implemented in it.

The first four classes are in the package named “com.tictactoe.components” , while the main class is in the package named “com.tictactoe”.

First we discuss the move class:

### Move:

Move made by either of the players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 package com.tictactoe.components;   /** * * @author pratyush */ public class Move {   private int row, column; private boolean isValid;   public int getRow() { return row; }   public void setRow(int row) { this.row = row; }   public int getColumn() { return column; }   public void setColumn(int column) { this.column = column; }   public boolean isIsValid() { return isValid; }   public void setIsValid(boolean isValid) { this.isValid = isValid; }   }```

Then comes the Board class where the moves are made.

### Board:

The board on which the game is played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 package com.tictactoe.components;   /** * * @author pratyush */ public class Board {   private static char[][] cells;   public Board() { cells = new char[3][3];   cells[0] = new char[]{' ', ' ', ' '};   cells[1] = new char[]{' ', ' ', ' '};   cells[2] = new char[]{' ', ' ', ' '}; }     public void display() { for(int i = 0; i < 3; i++) { for(int j = 0; j < 3; j++) {   if(cells[i][j] == ' ') {   System.out.print((i+1)+", "+(j+1)+"\t");   } else {   System.out.print(cells[i][j]+"\t");   }   } System.out.print("\n\n");   }   }   public Move checkAvailable(Move move) {   int i = move.getRow();   int j = move.getColumn();   boolean boundValid = ((i >= 1 && i<= 3) && ( j >= 1 && j <= 3));   boolean charValid = false;   if(boundValid) { charValid = (cells[i - 1][j - 1] == ' '); }   boolean netValid = (boundValid && charValid);   move.setIsValid(netValid);   return move; }   public void markCell(Move move, char mark) { if(move.isIsValid()) { int i = move.getRow();   int j = move.getColumn();   cells[i - 1][j - 1] = mark; } else { System.out.println("INVALID MOVE!\n\n"); } }   }```

The Player class denotes the players who make moves on the board.

### Player:

Either of the two players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 package com.tictactoe.components;   import java.util.ArrayList; /** * * @author pratyush */ public class Player {   private int playerNum; private char playerMark; private int winnerOrLoser; private Game g;   private ArrayList<Move> moves = new ArrayList<Move>();   public int getPlayerNum() { return playerNum; }   public void setPlayerNum(int playerNum) { this.playerNum = playerNum; }   public char getPlayerMark() { return playerMark; }   public void setPlayerMark(char playerMark) { this.playerMark = playerMark; }   public int getWinnerOrLoser() { return winnerOrLoser; }   public void setWinnerOrLoser(int winnerOrLoser) { this.winnerOrLoser = winnerOrLoser; }   public Game getGame() { return g; }   public void setGame(Game g) { this.g = g; }   public ArrayList getMoves() { return moves; }   public void addMove(Move move) {   this.moves.add(move); }   public void makeMove(Board board, Move move) { move = board.checkAvailable(move);   char mark = this.getPlayerMark();   board.markCell(move, mark);   if(move.isIsValid()) { this.addMove(move); Game.setMovesTillNow(); }   board.display(); }   }```

The Game class is the functionality of the game with all its rules.

### Game:

The game being played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 package com.tictactoe.components;   import java.util.ArrayList; /** * * @author pratyush */ public class Game {   private int whoseTurn; private static int movesTillNow = 0; private boolean gameOver;   private Player winner = null;   Move[][] winning_moves;   public Game() {   winning_moves = new Move[8][3];   //top row Move move01 = new Move(); move01.setRow(1); move01.setColumn(1);   Move move02 = new Move(); move02.setRow(1); move02.setColumn(2);   Move move03 = new Move(); move03.setRow(1); move03.setColumn(3);   Move[] move0;   move0 = new Move[]{move01, move02, move03};     winning_moves[0] = move0;   //middle row   Move move11 = new Move(); move11.setRow(2); move11.setColumn(1);   Move move12 = new Move(); move12.setRow(2); move12.setColumn(2);   Move move13 = new Move(); move13.setRow(2); move13.setColumn(3);   Move[] move1;   move1 = new Move[]{move11, move12, move13};   winning_moves[1] = move1;   //bottom row   Move move21 = new Move(); move21.setRow(3); move21.setColumn(1);   Move move22 = new Move(); move22.setRow(3); move22.setColumn(2);   Move move23 = new Move(); move23.setRow(3); move23.setColumn(3);   Move[] move2;   move2 = new Move[]{move21, move22, move23};   winning_moves[2] = move2;   //column wise   //column 1   Move move31 = new Move(); move31.setRow(1); move31.setColumn(1);   Move move32 = new Move(); move32.setRow(2); move32.setColumn(1);   Move move33 = new Move(); move33.setRow(3); move33.setColumn(1);   Move[] move3;   move3 = new Move[]{move31, move32, move33};   winning_moves[3] = move3;   //column 2   Move move41 = new Move(); move41.setRow(1); move41.setColumn(2);   Move move42 = new Move(); move42.setRow(2); move42.setColumn(2);   Move move43 = new Move(); move43.setRow(3); move43.setColumn(2);   Move[] move4;   move4 = new Move[]{move41, move42, move43};   winning_moves[4] = move4;   //column 3   Move move51 = new Move(); move51.setRow(1); move51.setColumn(3);   Move move52 = new Move(); move52.setRow(2); move52.setColumn(3);   Move move53 = new Move(); move53.setRow(3); move53.setColumn(3);   Move[] move5;   move5 = new Move[]{move51, move52, move53};   winning_moves[5] = move5;   //diagonals   //diagonal 1   Move move61 = new Move(); move61.setRow(1); move61.setColumn(1);   Move move62 = new Move(); move62.setRow(2); move62.setColumn(2);   Move move63 = new Move(); move63.setRow(3); move63.setColumn(3);   Move[] move6;   move6 = new Move[]{move61, move62, move63};   winning_moves[6] = move6;   //diagonal 2   Move move71 = new Move(); move71.setRow(1); move71.setColumn(3);   Move move72 = new Move(); move72.setRow(2); move72.setColumn(2);   Move move73 = new Move(); move73.setRow(3); move73.setColumn(1);   Move[] move7;   move7 = new Move[]{move71, move72, move73};   winning_moves[7] = move7;   }   public int getWhoseTurn() { return whoseTurn; }   public void setWhoseTurn(Player player) { this.whoseTurn = player.getPlayerNum(); }   public static int getMovesTillNow() { return movesTillNow; }   public static void setMovesTillNow() { Game.movesTillNow++; }   public boolean isGameOver() { return gameOver; }   public void setGameOver(boolean gameOver) { this.gameOver = gameOver; }   public Player getWinner() { return winner; }   public void setWinner(Player winner) { this.winner = winner; }   private boolean checkSubset(Move[] subset, Move[] winning_row) { int count = 0;   for(int i = 0;i < 3; i++) { for(int j = 0; j< 3; j++) { if(subset[i].getRow() == winning_row[j].getRow() && subset[i].getColumn() == winning_row[j].getColumn()) { count++; } } }   return (count == 3); }     //check the winning moves   public boolean checkWinningMoves(Player player) {   /*****check winning moves*****/   int movesTillNow = Game.getMovesTillNow();   int whoseTurn = this.getWhoseTurn();   ArrayList<Move> playerMoves = player.getMoves();   int moves = movesTillNow;   Move[][] winning_moves1 = this.winning_moves;   switch(whoseTurn) { case 1:   if(moves < 5) { return false; } else { if(moves == 5) { Move[] player1_set1 = new Move[]{playerMoves.get(0), playerMoves.get(1), playerMoves.get(2)};   for(int i = 0; i< 8; i++) { if(checkSubset(player1_set1, winning_moves1[i])) { return true; } } }   /******/   if(moves == 7) { Move[] player1_set2 = new Move[]{playerMoves.get(0), playerMoves.get(1), playerMoves.get(3)};   Move[] player1_set4 = new Move[]{playerMoves.get(0), playerMoves.get(2), playerMoves.get(3)};   Move[] player1_set7 = new Move[]{playerMoves.get(1), playerMoves.get(2), playerMoves.get(3)};   for(int i = 0; i < 8; i++) { if(checkSubset(player1_set2, winning_moves1[i]) || checkSubset(player1_set4, winning_moves1[i]) || checkSubset(player1_set7, winning_moves1[i]) ) { return true; } } }   if(moves == 9) { Move[] player1_set3 = new Move[]{playerMoves.get(0), playerMoves.get(1), playerMoves.get(4)};   Move[] player1_set5 = new Move[]{playerMoves.get(0), playerMoves.get(2), playerMoves.get(4)};   Move[] player1_set6 = new Move[]{playerMoves.get(0), playerMoves.get(3), playerMoves.get(4)};   Move[] player1_set8 = new Move[]{playerMoves.get(1), playerMoves.get(2), playerMoves.get(4)};   Move[] player1_set9 = new Move[]{playerMoves.get(1), playerMoves.get(3), playerMoves.get(4)};   Move[] player1_set10 = new Move[]{playerMoves.get(2), playerMoves.get(3), playerMoves.get(4)};   for(int i = 0; i < 8; i++) { if(checkSubset(player1_set3, winning_moves1[i]) || checkSubset(player1_set5, winning_moves1[i]) || checkSubset(player1_set6, winning_moves1[i]) || checkSubset(player1_set8, winning_moves1[i]) || checkSubset(player1_set9, winning_moves1[i]) || checkSubset(player1_set10, winning_moves1[i])) { return true; } } }   return false; }   case 2: /******/ if(moves < 6) { return false; } else { /*******/ if(moves == 6) { Move[] player2_set1 = new Move[]{playerMoves.get(0), playerMoves.get(1), playerMoves.get(2)};   for(int i = 0; i < 8; i++) { if(checkSubset(player2_set1, winning_moves1[i])) { return true; } } }   if(moves == 8) { Move[] player2_set2 = new Move[]{playerMoves.get(0), playerMoves.get(1), playerMoves.get(3)};   Move[] player2_set3 = new Move[]{playerMoves.get(0), playerMoves.get(2), playerMoves.get(3)};   Move[] player2_set4 = new Move[]{playerMoves.get(1), playerMoves.get(2), playerMoves.get(3)};   for(int i = 0; i < 8; i++) { if(checkSubset(player2_set2, winning_moves1[i]) || checkSubset(player2_set3, winning_moves1[i]) || checkSubset(player2_set4, winning_moves1[i])) { return true; } } }   return false; } default: return false; } }   }```

Finally, the main class:

### TicTacToe

The class containing the entry point of the program also called the main class.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 package com.tictactoe;   import com.tictactoe.components.*; import java.util.Scanner; /** * * @author pratyush */ public class TicTacToe {   /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here   Game game = new Game();   Player player1 = new Player();   player1.setPlayerNum(1);   player1.setPlayerMark('X');   player1.setGame(game);   Player player2 = new Player();   player2.setPlayerNum(2);   player2.setPlayerMark('0');   player2.setGame(game);   Board board = new Board();   board.display();   /*******/   game.setWhoseTurn(player1);   game.setGameOver(false);   boolean status = game.isGameOver();   Scanner sc = new Scanner(System.in);   do { int movesNow = Game.getMovesTillNow();   if(movesNow == 9) { if(game.getWinner() == null) { System.out.println("TIE!\n"); break; } }   int turn = game.getWhoseTurn();   System.out.println("PLAYER "+turn+"\n");   int row = 0; int column = 0;   boolean invalid = true;   while(invalid) { //code to handle invalid moves. players cannot proceed without valid input try{ System.out.println("Enter row: ");   String str = sc.next();   if(!str.equals("")) {   row = Integer.parseInt(str); invalid = false;   } else { continue; } } catch(NumberFormatException n) { System.out.println("INVALID ROW!"); invalid = true; } catch(InputMismatchException i) { System.out.println("INVALID ROW!"); invalid = true; } }   invalid = true;   while(invalid) { /*code to handle invalid moves. players cannot proceed without valid input*/   try{ System.out.println("Enter column: ");   String str = sc.next();   if(!str.equals("")) {   column = Integer.parseInt(str); invalid = false;   } else { continue; } } catch(NumberFormatException n) { System.out.println("INVALID COLUMN!"); invalid = true; } catch(InputMismatchException i) { System.out.println("INVALID COLUMN!"); invalid = true; } }   /**/   Move move = new Move();   move.setRow(row);   move.setColumn(column);   switch(turn) { case 1: player1.makeMove(board, move);   if(game.checkWinningMoves(player1)) { game.setWinner(player1);   System.out.println("PLAYER 1 WINS!");   game.setGameOver(true); } else { if(move.isIsValid()) { movesNow = Game.getMovesTillNow();   System.out.println("MOVE NUMBER "+movesNow+"\n");   game.setWhoseTurn(player2); } } break; case 2: player2.makeMove(board, move);   if(game.checkWinningMoves(player2)) { game.setWinner(player2);   System.out.println("PLAYER 2 WINS!");   game.setGameOver(true); } else { if(move.isIsValid()) { movesNow = Game.getMovesTillNow();   System.out.println("MOVE NUMBER "+movesNow+"\n");   game.setWhoseTurn(player1); } } break; default: System.out.println("ERROR!\n"); break; }   status = game.isGameOver(); } while(!status);   }   }```

Copy, Compile, Run and ENJOY!

### C# version

Here is an elementary tic-tac-toe or noughts and crosses game I made in C#, arguably the most popular language of the DotNET platform. It can be played from the command line after compiling it as an executable. In the game of tic-tac-toe there is a 3X3 grid or board.The game is for two players. The players 1 and 2 take turns to mark the cells of the grid with their mark which is a zero or a cross.

The first player to complete a vertical, horizontal or diagonal triad of zeroes or crosses, wins.

The PHP version can be found here

Player makes Move on Board to play Game. So the classes are:

1. Move
2. Board
3. Player
4. Game
5. TicTacToe

There is one new class “TicTacToe” because C# needs a main class having the “Main” method implemented in it.

The classes are in the namespace called “TicTacToeDotNet”.

First we discuss the move class:

### Move:

Move made by either of the players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace TicTacToeDotNet { public class Move {   private int row, column; private bool isValid;   public int getRow() { return row; }   public void setRow(int row) { this.row = row; }   public int getColumn() { return column; }   public void setColumn(int column) { this.column = column; }   public bool isIsValid() { return isValid; }   public void setIsValid(bool isValid) { this.isValid = isValid; }   } }```

Then comes the Board class where the moves are made.

### Board:

The board on which the game is played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace TicTacToeDotNet { public class Board {   private static char[][] cells;   public Board() { cells = new char[3][];   cells[0] = new char[] { ' ', ' ', ' ' };   cells[1] = new char[] { ' ', ' ', ' ' };   cells[2] = new char[] { ' ', ' ', ' ' }; }     public void display() { for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) {   if (cells[i][j] == ' ') {   Console.Write((i + 1) + ", " + (j + 1) + "\t");   } else {   Console.Write(cells[i][j] + "\t");   }   } Console.Write("\n\n");   }   }   public Move checkAvailable(Move move) {   int i = move.getRow();   int j = move.getColumn();   bool boundValid = ((i >= 1 && i <= 3) && (j >= 1 && j <= 3));   bool charValid = false;   if (boundValid) { charValid = (cells[i - 1][j - 1] == ' '); }   bool netValid = (boundValid && charValid);   move.setIsValid(netValid);   return move; }   public void markCell(Move move, char mark) { if (move.isIsValid()) { int i = move.getRow();   int j = move.getColumn();   cells[i - 1][j - 1] = mark; } else { Console.Write("INVALID MOVE!\n\n"); } }   }   }```

The Player class denotes the players who make moves on the board.

### Player:

Either of the two players.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 using System; using System.Collections; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace TicTacToeDotNet { public class Player {   private int playerNum; private char playerMark; private int winnerOrLoser; private Game g;   private List moves = new List();   public int getPlayerNum() { return playerNum; }   public void setPlayerNum(int playerNum) { this.playerNum = playerNum; }   public char getPlayerMark() { return playerMark; }   public void setPlayerMark(char playerMark) { this.playerMark = playerMark; }   public int getWinnerOrLoser() { return winnerOrLoser; }   public void setWinnerOrLoser(int winnerOrLoser) { this.winnerOrLoser = winnerOrLoser; }   public Game getGame() { return g; }   public void setGame(Game g) { this.g = g; }   public List getMoves() { return moves; }   public void addMove(Move move) {   this.moves.Add(move); }   public void makeMove(Board board, Move move) { move = board.checkAvailable(move);   char mark = this.getPlayerMark();   board.markCell(move, mark);   if (move.isIsValid()) { this.addMove(move); Game.setMovesTillNow(); }   board.display(); }   } }```

The Game class is the functionality of the game with all its rules.

### Game:

The game being played.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace TicTacToeDotNet { public class Game {   private int whoseTurn; private static int movesTillNow = 0; private bool gameOver;   private Player winner = null;   Move[][] winning_moves;   public Game() {   winning_moves = new Move[8][];   //top row Move move01 = new Move(); move01.setRow(1); move01.setColumn(1);   Move move02 = new Move(); move02.setRow(1); move02.setColumn(2);   Move move03 = new Move(); move03.setRow(1); move03.setColumn(3);   Move[] move0;   move0 = new Move[] { move01, move02, move03 };     winning_moves[0] = move0;   //middle row   Move move11 = new Move(); move11.setRow(2); move11.setColumn(1);   Move move12 = new Move(); move12.setRow(2); move12.setColumn(2);   Move move13 = new Move(); move13.setRow(2); move13.setColumn(3);   Move[] move1;   move1 = new Move[] { move11, move12, move13 };   winning_moves[1] = move1;   //bottom row   Move move21 = new Move(); move21.setRow(3); move21.setColumn(1);   Move move22 = new Move(); move22.setRow(3); move22.setColumn(2);   Move move23 = new Move(); move23.setRow(3); move23.setColumn(3);   Move[] move2;   move2 = new Move[] { move21, move22, move23 };   winning_moves[2] = move2;   //column wise   //column 1   Move move31 = new Move(); move31.setRow(1); move31.setColumn(1);   Move move32 = new Move(); move32.setRow(2); move32.setColumn(1);   Move move33 = new Move(); move33.setRow(3); move33.setColumn(1);   Move[] move3;   move3 = new Move[] { move31, move32, move33 };   winning_moves[3] = move3;   //column 2   Move move41 = new Move(); move41.setRow(1); move41.setColumn(2);   Move move42 = new Move(); move42.setRow(2); move42.setColumn(2);   Move move43 = new Move(); move43.setRow(3); move43.setColumn(2);   Move[] move4;   move4 = new Move[] { move41, move42, move43 };   winning_moves[4] = move4;   //column 3   Move move51 = new Move(); move51.setRow(1); move51.setColumn(3);   Move move52 = new Move(); move52.setRow(2); move52.setColumn(3);   Move move53 = new Move(); move53.setRow(3); move53.setColumn(3);   Move[] move5;   move5 = new Move[] { move51, move52, move53 };   winning_moves[5] = move5;   //diagonals   //diagonal 1   Move move61 = new Move(); move61.setRow(1); move61.setColumn(1);   Move move62 = new Move(); move62.setRow(2); move62.setColumn(2);   Move move63 = new Move(); move63.setRow(3); move63.setColumn(3);   Move[] move6;   move6 = new Move[] { move61, move62, move63 };   winning_moves[6] = move6;   //diagonal 2   Move move71 = new Move(); move71.setRow(1); move71.setColumn(3);   Move move72 = new Move(); move72.setRow(2); move72.setColumn(2);   Move move73 = new Move(); move73.setRow(3); move73.setColumn(1);   Move[] move7;   move7 = new Move[] { move71, move72, move73 };   winning_moves[7] = move7;   }   public int getWhoseTurn() { return whoseTurn; }   public void setWhoseTurn(Player player) { this.whoseTurn = player.getPlayerNum(); }   public static int getMovesTillNow() { return movesTillNow; }   public static void setMovesTillNow() { Game.movesTillNow++; }   public bool isGameOver() { return gameOver; }   public void setGameOver(bool gameOver) { this.gameOver = gameOver; }   public Player getWinner() { return winner; }   public void setWinner(Player winner) { this.winner = winner; }   private bool checkSubset(Move[] subset, Move[] winning_row) { int count = 0;   for (int i = 0; i < 3; i++) { for (int j = 0; j < 3; j++) { if (subset[i].getRow() == winning_row[j].getRow() && subset[i].getColumn() == winning_row[j].getColumn()) { count++; } } }   return (count == 3); }     //check the winning moves   public bool checkWinningMoves(Player player) {   /*****check winning moves*****/   int movesTillNow = Game.getMovesTillNow();   int whoseTurn = this.getWhoseTurn();   Move[] playerMoves = player.getMoves().ToArray();   int moves = movesTillNow;   Move[][] winning_moves1 = this.winning_moves;   switch (whoseTurn) { case 1:   if (moves < 5) { return false; } else { if (moves == 5) { Move[] player1_set1 = new Move[] { playerMoves[0], playerMoves[1], playerMoves[2] };   for (int i = 0; i < 8; i++) { if (checkSubset(player1_set1, winning_moves1[i])) { return true; } } }   /******/   if (moves == 7) { Move[] player1_set2 = new Move[] { playerMoves[0], playerMoves[1], playerMoves[3] };   Move[] player1_set4 = new Move[] { playerMoves[0], playerMoves[2], playerMoves[3] };   Move[] player1_set7 = new Move[] { playerMoves[1], playerMoves[2], playerMoves[3] };   for (int i = 0; i < 8; i++) { if (checkSubset(player1_set2, winning_moves1[i]) || checkSubset(player1_set4, winning_moves1[i]) || checkSubset(player1_set7, winning_moves1[i])) { return true; } } }   if (moves == 9) { Move[] player1_set3 = new Move[] { playerMoves[0], playerMoves[1], playerMoves[4] };   Move[] player1_set5 = new Move[] { playerMoves[0], playerMoves[2], playerMoves[4] };   Move[] player1_set6 = new Move[] { playerMoves[0], playerMoves[3], playerMoves[4] };   Move[] player1_set8 = new Move[] { playerMoves[1], playerMoves[2], playerMoves[4] };   Move[] player1_set9 = new Move[] { playerMoves[1], playerMoves[3], playerMoves[4] };   Move[] player1_set10 = new Move[] { playerMoves[2], playerMoves[3], playerMoves[4] };   for (int i = 0; i < 8; i++) { if (checkSubset(player1_set3, winning_moves1[i]) || checkSubset(player1_set5, winning_moves1[i]) || checkSubset(player1_set6, winning_moves1[i]) || checkSubset(player1_set8, winning_moves1[i]) || checkSubset(player1_set9, winning_moves1[i]) || checkSubset(player1_set10, winning_moves1[i])) { return true; } } }   return false; }   case 2: /******/ if (moves < 6) { return false; } else { /*******/ if (moves == 6) { Move[] player2_set1 = new Move[] { playerMoves[0], playerMoves[1], playerMoves[2] };   for (int i = 0; i < 8; i++) { if (checkSubset(player2_set1, winning_moves1[i])) { return true; } } }   if (moves == 8) { Move[] player2_set2 = new Move[] { playerMoves[0], playerMoves[1], playerMoves[3] };   Move[] player2_set3 = new Move[] { playerMoves[0], playerMoves[2], playerMoves[3] };   Move[] player2_set4 = new Move[] { playerMoves[1], playerMoves[2], playerMoves[3] };   for (int i = 0; i < 8; i++) { if (checkSubset(player2_set2, winning_moves1[i]) || checkSubset(player2_set3, winning_moves1[i]) || checkSubset(player2_set4, winning_moves1[i])) { return true; } } }   return false; } default: return false; } }   } }```

Finally, the main class:

### TicTacToe

The class containing the entry point of the program also called the main class.

```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 using System; using System.Collections.Generic; using System.Linq; using System.Text; using System.Threading.Tasks;   namespace TicTacToeDotNet { public class TicTacToe {   /** * @param args the command line arguments */ public static void Main(string[] args) { // TODO code application logic here   Game game = new Game();   Player player1 = new Player();   player1.setPlayerNum(1);   player1.setPlayerMark('X');   player1.setGame(game);   Player player2 = new Player();   player2.setPlayerNum(2);   player2.setPlayerMark('0');   player2.setGame(game);   Board board = new Board();   board.display();   /*******/   game.setWhoseTurn(player1);   game.setGameOver(false);   bool status = game.isGameOver();   //   do { int movesNow = Game.getMovesTillNow();   if (movesNow == 9) { if (game.getWinner() == null) { Console.WriteLine("TIE!\n"); break; } }   int turn = game.getWhoseTurn();   Console.WriteLine("PLAYER " + turn + "\n");   int row = 0; int column = 0;   bool invalid = true;   while (invalid) { //code to handle invalid moves. players cannot proceed without valid input try { Console.WriteLine("Enter row: ");   string str = Convert.ToString(Console.ReadLine());   if (!(str == "")) {   row = Convert.ToInt32(str); invalid = false;   } else { continue; } } catch (FormatException n) { Console.WriteLine("INVALID ROW!"); invalid = true; } /**/ }   invalid = true;   while (invalid) { /*code to handle invalid moves. players cannot proceed without valid input*/   try { Console.WriteLine("Enter column: ");   String str = Convert.ToString(Console.ReadLine());   if (!(str == "")) {   column = Convert.ToInt32(str); invalid = false;   } else { continue; } } catch (FormatException n) { Console.WriteLine("INVALID COLUMN!"); invalid = true; } /**/ }   /**/   Move move = new Move();   move.setRow(row);   move.setColumn(column);   switch (turn) { case 1: player1.makeMove(board, move);   if (game.checkWinningMoves(player1)) { game.setWinner(player1);   Console.WriteLine("PLAYER 1 WINS!");   game.setGameOver(true); } else { if (move.isIsValid()) { movesNow = Game.getMovesTillNow();   Console.WriteLine("MOVE NUMBER " + movesNow + "\n");   game.setWhoseTurn(player2); } } break; case 2: player2.makeMove(board, move);   if (game.checkWinningMoves(player2)) { game.setWinner(player2);   Console.WriteLine("PLAYER 2 WINS!");   game.setGameOver(true); } else { if (move.isIsValid()) { movesNow = Game.getMovesTillNow();   Console.WriteLine("MOVE NUMBER " + movesNow + "\n");   game.setWhoseTurn(player1); } } break; default: Console.WriteLine("ERROR!\n"); break; }   status = game.isGameOver(); } while (!status);   Console.Read();   }   } }```

Copy, Compile, Run and ENJOY!