BoardJava

package TicTacToe;

public class Board {
    public final int BLANK = 0;
    public final int X = 1;
    public final int O = -1;
    public int movesMade = 0;

    private int[] played = new int[9];
    private Square[] squares = new Square[9];

    public Board() {
        for (int p: played) { p = 0; }
        for (int i = 1; i <= 9; i++) {
            squares[i-1] = new Square(i);
        }
        this.movesMade = 0;
        System.out.println("This board has been created.");

    }

    public void clearSquare(int position) {
        squares[position-1].clear();
    }

    public void clearBoard() {
        for (int p: played) { p = 0; }
        for (int i = 1; i <= 9; i++) {
            squares[i-1] = new Square(i);
        }
        this.movesMade = 0;
        System.out.println("This board has been cleared.");
    }

    public boolean move(int player, int position) { // plays an X or O in the designated square
        assert (player == X || player == O);

        int index = position-1;
        Square sq = squares[index];
        if (sq.getState() != BLANK) {
            System.out.println("That square is occupied!");
            return false;
        }

        if (player == X) {
            sq.playX();
            System.out.println("X in square " + position);
        }
        if (player == O) {
            sq.playO();
            System.out.println("O in square " + position);
        }

        movesMade ++;
        return true;
    }

    public Board result(int player, int position) { // plays an X or O in the designated square
        assert (player == X || player == O);

        int index = position-1;
        Square sq = squares[index];
        if (sq.getState() != BLANK) {
            System.out.println("That square is occupied!");
            return null;
        }

        if (player == X) {
            sq.playX();
            //System.out.println("X in square " + position);
        }
        if (player == O) {
            sq.playO();
            //System.out.println("O in square " + position);
        }

        movesMade ++;
        return this;
    }

    public int[] getAllStates() { // Returns an array of all spaces' (0-8) contents
        int[] states = new int[9];
        for (int i = 0; i < 9; i++) {
            int st = squares[i].getState();
            assert st == X || st == O || st == BLANK; // Ensure win conditions will work
            states[i] = st;
        }

        return states;
    }

    public int[] emptySquares() { // Returns an array of all empty positions (possible actions)
        int empty = 9 - movesMade;
        if (empty == 0) return null;

        int[] blanks = new int[empty];
        int index = 0;
        for (Square sq: squares) {
            if (sq.getState() == BLANK) {
                blanks[index] = sq.getPosition();
                index ++;
            }
        }

        return blanks;
    }

    public String toString() { // Create a string to represent the whole board
        String str = "";
        //str += "TicTacToe";
        for (int i = 1; i <= 9; i++) {
            int sq = i-1;
            if (i == 1 || i == 4 || i == 7) str += "\n|" + squares[sq].print() + "|";
            else str += squares[sq].print() + "|";
        }

        return str + "\n";
    }

    public void showBoard() { // Print the whole board
        System.out.println(this.toString());
    }

    public int whoWon() { // Returns O if O won, X if X won, or BLANK is nobody has won
        // All sets of three: ROWS 0,1,2; 3,4,5; 6,7,8; COLUMNS 0,3,6; 1,4,7; 2,5,8; DIAGONALS 0,4,8; 2,4,6
        // Adding the lines of three will give 3 if X wins, -3 if O wins

        int[] T = getAllStates();
        int center = T[4];

        if (center != BLANK) { // Check diagonals
            if (center + T[0] + T[8] == 3)      { return X; }   // NW to SE
            if (center + T[0] + T[8] == -3)     { return O; }
            if (center + T[2] + T[6] == 3)      { return X; }   // NE to SW
            if (center + T[2] + T[6] == -3)     { return O; }
        }

        for (int s = 0; s <= 6; s += 3) {
            if (T[s] + T[s+1] + T[s+2] == 3)    { return X; }   // Horizontal
            if (T[s] + T[s+1] + T[s+2] == -3)   { return O; }
        }

        for (int s = 0; s <= 2; s ++) {
            if (T[s] + T[s+3] + T[s+6] == 3)    { return X; }   // Vertical
            if (T[s] + T[s+3] + T[s+6] == -3)   { return O; }
        }

        System.out.println("Nobody has won yet...");
        return BLANK;
    }

    public int numTwos(int player) { // Returns the number of twos on the board for the given player
        // All sets of three: ROWS 0,1,2; 3,4,5; 6,7,8; COLUMNS 0,3,6; 1,4,7; 2,5,8; DIAGONALS 0,4,8; 2,4,6
        // Adding the lines of three will give 2 if X has two, -2 if O has two
        assert (player == X || player == O);
        if (movesMade < 3) { return 0; } // No twos can exist unless 3 moves were made.

        int twos = 0;
        int want = 2*player; // -2 for O, 2 for X

        int[] T = getAllStates();

        // Check diagonals
        if (T[4] + T[0] + T[8] == want)     { twos ++; }    // NW to SE
        if (T[4] + T[2] + T[6] == want)     { twos ++; }    // NE to SW

        for (int s = 0; s <= 6; s += 3) {
            if (T[s] + T[s+1] + T[s+2] == want)     { twos ++; }    // Horizontal
        }

        for (int s = 0; s <= 2; s ++) {
            if (T[s] + T[s+3] + T[s+6] == want)     { twos ++; }    // Vertical
        }

        String pstr = (player == X) ? "X" : "O";
        System.out.println(pstr + " has " + twos + " twos.");
        return twos;
    }

    public int whereToBlock(int opponent) { // Returns 0 if enemy has no twos, or a position to block them.
        // All sets of three: ROWS 0,1,2; 3,4,5; 6,7,8; COLUMNS 0,3,6; 1,4,7; 2,5,8; DIAGONALS 0,4,8; 2,4,6
        // Adding the lines of three will give 2 if X has two, -2 if O has two
        assert (opponent == X || opponent == O);
        if (movesMade < 3) { return 0; } // No twos can exist unless 3 moves were made.

        int enemyTwos = 0;
        int want = 2*opponent; // 2 for O, -2 for X
        int blockPos = 0;

        int[] T = getAllStates();

        // Check diagonals
        if (T[0] + T[4] + T[8] == want) { // NW to SE
            enemyTwos ++;
            for (int k = 0; k <= 8; k += 4) { // find the blank, set blockPos to that position
                if (T[k] == BLANK) { blockPos = k+1; break; }
            }
        }
        if (T[2] + T[4] + T[6] == want) { // NE to SW
            enemyTwos ++;
            for (int k = 0; k <= 6; k += 2) { // find the blank, set blockPos to that position
                if (T[k] == BLANK) { blockPos = k+1; break; }
            }
        }

        for (int s = 0; s <= 6; s += 3) { // Horizontal
            if (T[s] + T[s+1] + T[s+2] == want) {
                enemyTwos ++;
                for (int k = s; k <= s+2; k += 1) { // find the blank, set blockPos to that position
                    if (T[k] == BLANK) { blockPos = k+1; break; }
                }
            }
        }

        for (int s = 0; s <= 2; s ++) { // Vertical
            if (T[s] + T[s+3] + T[s+6] == want) {
                enemyTwos ++;
                for (int k = s; k <= s+6; k += 3) { // find the blank, set blockPos to that position
                    if (T[k] == BLANK) { blockPos = k+1; break; }
                }
            }
        }

        String pstr = (opponent == X) ? "X" : "O";
        System.out.println(pstr + " has " + enemyTwos + " twos.");
        if (enemyTwos < 1) { return 0; }
        else {
            System.out.println("Must block at position " + blockPos + "!");
        }

        return blockPos;
    }


}