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// **THIS IS AN EXAMPLE IMPLEMENTATION!**
// Brett Wortzman
// CSE 123
// C0: Abstract Strategy Games
//
// A class to represent a game of tic-tac-toe that implements the
// AbstractStrategyGame interface.
import java.util.*;
public class TicTacToe extends AbstractStrategyGame {
private char[][] board;
private boolean isXTurn;
// Constructs a new TicTacToe game.
public TicTacToe() {
board = new char[][]{{'-', '-', '-'},
{'-', '-', '-'},
{'-', '-', '-'}};
isXTurn = true;
}
// Returns whether or not the game is over.
public boolean isGameOver() {
return getWinner() >= 0;
}
// Returns the index of the winner of the game.
// 1 if player 1 (X), 2 if player 2 (O), 0 if a tie occurred,
// and -1 if the game is not over.
public int getWinner() {
for (int i = 0; i < board.length; i++) {
// check row i
if (board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] != '-') {
return board[i][0] == 'X' ? 1 : 2;
}
// check col i
if (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] != '-') {
return board[0][i] == 'X' ? 1 : 2;
}
}
// check diagonals
if (board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] != '-') {
return board[0][0] == 'X' ? 1 : 2;
}
if (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] != '-') {
return board[0][2] == 'X' ? 1 : 2;
}
// check for tie
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board[i].length; j++) {
if (board[i][j] == '-') {
// unfilled space; game not over
return -1;
}
}
}
// it's a tie!
return 0;
}
// Returns the index of which player's turn it is.
// 1 if player 1 (X), 2 if player 2 (O), -1 if the game is over
public int getNextPlayer() {
if (isGameOver()) {
return -1;
}
return isXTurn ? 1 : 2;
}
// Given the input, places an X or an O where
// the player specifies.
// Throws an IllegalArgumentException if the position is
// invalid, whether that be out of bounds or already occupied.
// Board bounds are [0, 2] for both rows and cols.
public void makeMove(Scanner input) {
char currPlayer = isXTurn ? 'X' : 'O';
System.out.print("Row? ");
int row = input.nextInt();
System.out.print("Column? ");
int col = input.nextInt();
makeMove(row, col, currPlayer);
isXTurn = !isXTurn;
}
// Private helper method for makeMove.
// Given a row and col, as well as player index,
// places an X or an O in that row and col.
// Throws an IllegalArgumentException if the position is
// invalid, whether that be out of bounds or already occupied.
// Board bounds are [0, 2] for both rows and cols.
private void makeMove(int row, int col, char player) {
if (row < 0 || row >= board.length ||
col < 0 || col >= board[0].length) {
throw new IllegalArgumentException("Invalid board position: " + row + "," + col);
}
if (board[row][col] != '-') {
throw new IllegalArgumentException("Space already occupied: " + row + "," + col);
}
board[row][col] = player;
}
// Returns a String containing instructions to play the game.
public String instructions() {
String result = "";
result += "Player 1 is X and goes first. Choose where to play by entering a row and\n";
result += "column number, where (0, 0) is the upper left and (2, 2) is the lower right.\n";
result += "Spaces show as a - are empty. The game ends when one player marks three spaces\n";
result += "in a row, in which case that player wins, or when the board is full, in which\n";
result += "case the game ends in a tie.";
return result;
}
// Returns a String representation of the current state of the board.
public String toString() {
String result = "";
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board.length; j++) {
result += board[i][j] + " ";
}
result += "\n";
}
return result;
}
}
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