Nested loop infinitely looping after random interval? - java

I am programming a connect 4 game using Java for an assignment. However, whenever player 2 makes a move about 5 moves in, the player 2 loop will infinitely loop. There is some sort of logic error that I cannot find, and it is frustrating. What is the logic error, and what is a good way to avoid future mistakes of the same vain?
I have tried changing the variables for the do > while loop where player 1 and player two attempt their moves. However that has no affect on it.
import java.util.Arrays;
public class Lab6Shell {
public static void main(String args[]) {
// variables
Scanner input = new Scanner(System.in);
char[][] board = new char[7][8];
boolean finished = false;
boolean gameOver = false;
int width = 7;
int height = 8;
char currentPlayer = 'X';
int numMoves = 0;
int bottom_row = width - 1;
// loop until user wants to stop
for (int row = 0; row < board.length; row++) {
java.util.Arrays.fill(board[row], 0, board[row].length, '*');
}
do {
// display the board
DisplayBoard(board);
// loop until this game is over
do {
// get the next move for the current player
int columnChosen = 0;
do {
if (currentPlayer == 'X') {
int counter = 1;
System.out.println("Player 1 turn");
System.out.println("Enter the column you want to place your piece.");
columnChosen = input.nextInt();
input.nextLine();
while (true) {
if (columnChosen > width) {
System.out.println("That's not a valid column");
break;
}
if ((board[bottom_row][columnChosen] == '*')) {
board[bottom_row][columnChosen] = 'X';
break;
} else if ((board[bottom_row][columnChosen] == 'X')
|| (board[bottom_row][columnChosen] == 'O')) {
if (board[bottom_row - counter][columnChosen] == '*') { // puts X if blank
board[bottom_row - counter][columnChosen] = 'X';
break;
}
counter += 1;
if (counter == width) {
System.out.println("That column is full");
break;
}
}
}
}
if (currentPlayer == 'O') {
int counter = 1;
System.out.println("Player 2's turn");
System.out.println("Enter the column you want to place your piece.");
columnChosen = input.nextInt();
input.nextLine();
while (true) {
if (columnChosen > width) {
System.out.println("That's not a valid column");
break;
}
if ((board[bottom_row][columnChosen] == '*')) {
board[bottom_row][columnChosen] = 'O';
break;
} else if ((board[bottom_row][columnChosen] == 'X')
|| (board[bottom_row][columnChosen] == 'O')) {
if (board[bottom_row - counter][columnChosen] == '*') { // puts O
board[bottom_row - counter][columnChosen] = 'O';
break;
}
counter += 1;
if (counter == width) {
System.out.println("That column is full");
break;
}
}
}
}
} while (columnChosen < 0 || columnChosen > 8 || board[1][columnChosen] != '*');
// place piece
// increment number of moves
numMoves++;
// display the board
DisplayBoard(board);
// check for win
if (checkWin(board)) {
// if winner, display congratulations and set gameOver true
System.out.println("Congratulations! You won!");
gameOver = true;
} else if (numMoves == 42) {
// if tie, display result and set gameOver true
DisplayBoard(board);
System.out.println("Tie Game! Game over");
gameOver = true;
} else if (checkWin(board) == false) {
if (currentPlayer == ('X')) {
currentPlayer = ('O');
} else {
currentPlayer = ('X');
}
}
} while (!gameOver);
// ask if user wants to play again, set finished accordingly
System.out.println("Would you like to play again?");
input.nextLine();
String decision = input.nextLine();
if (decision.toLowerCase().equals("yes")) {
finished = false;
}
else if (decision.toLowerCase().equals("no")) {
finished = true;
}
} while (finished == false);
}
// this method displays the board passed in
public static void DisplayBoard(char[][] board) {
for (int i = 0; i < board.length; i++) {
System.out.print("|");
for (int j = 0; j < board[i].length; j++) {
System.out.print(" " + board[i][j] + "|");
}
System.out.println("");
}
}
public static boolean checkWin(char[][] board) {
final int HEIGHT = board.length;
final int WIDTH = board[0].length;
final int EMPTY_SLOT = '*';
for (int r = 0; r < HEIGHT; r++) { // iterate rows, bottom to top
for (int c = 0; c < WIDTH; c++) { // iterate columns, left to right
char player = board[r][c];
if (player == EMPTY_SLOT)
continue; // don't check empty slots
if (c + 3 < WIDTH && player == board[r][c + 1] && // look right
player == board[r][c + 2] && player == board[r][c + 3])
return true;
if (r + 3 < HEIGHT) {
if (player == board[r + 1][c] && // look up
player == board[r + 2][c] && player == board[r + 3][c])
return true;
if (c + 3 < WIDTH && player == board[r + 1][c + 1] && // look up & right
player == board[r + 2][c + 2] && player == board[r + 3][c + 3])
return true;
if (c - 3 >= 0 && player == board[r + 1][c - 1] && // look up & left
player == board[r + 2][c - 2] && player == board[r + 3][c - 3])
return true;
}
}
}
return false; // no winner found
}
}
The expected result is that each player will play a piece until four of the same piece are in a row. Then the first to reach four in a row is declared the winner, and the game ends. However, once the game gets in about 5 loops, the player 2 loop infinitely loops until a column is full, and does not print out the board.

Your infinite loop is caused by checking the condition board[1][columnChosen] != '*' in your do ... while loop. The program will continue to ask the current user for a new move as long as the second to top row of the selected column is occupied.
Replace:
do
{
...
} while (columnChosen < 0 || columnChosen > 8 || board[1][columnChosen] != '*');
With:
do
{
...
} while (columnChosen < 0 || columnChosen > 8)
This should get you to a point where you can tackle the remaining issues.

Related

my do-while loop seems to be running forever even though i change the value of the condition

boolean onGoing = true;
do {
String p1 = "playing";
while (p1.equals("playing")) {
System.out.println("Player 1, enter hit row/column:");
int a = sc.nextInt();
int b = sc.nextInt();
if (a >= 0 && a < 5 && b >= 0 && b < 5) {
if (history1[a][b] == '-') {
p1 += " no more";
if (board2[a][b] == '#') {
history1[a][b] = 'X';
board2[a][b] = 'X';
String status = check(board2);
if (status.equals("win")) {
System.out.println("PLAYER 1 WINS! YOU SUNK ALL OF YOUR OPPONENT'S SHIPS!");
onGoing = false;
printBattleShip(board1);
printBattleShip(board2);
break;
} else {
System.out.println("PLAYER 1 HIT PLAYER 2's SHIP!");
}
} else if (board2[a][b] == '-') {
System.out.println("PLAYER 1 MISSED!");
history1[a][b] = 'O';
board2[a][b] = 'O';
}
} else {
System.out.println("You already fired on this spot. Choose different coordinates.");
}
} else {
System.out.println("Invalid coordinates. Choose different coordinates.");
}
}
String p2 = "playing";
while (p2.equals("playing")) {
System.out.println("Player 2, enter hit row/column:");
int c = sc.nextInt();
int d = sc.nextInt();
if (c >= 0 && c < 5 && d >= 0 && d < 5) {
if (history2[c][d] == '-') {
p2 += " no more";
if (board1[c][d] == '#') {
history2[c][d] = 'X';
board1[c][d] = 'X';
String status = check(board1);
if (status.equals("win")) {
System.out.println("PLAYER 2 WINS! YOU SUNK ALL OF YOUR OPPONENT'S SHIPS!");
onGoing = false;
printBattleShip(board2);
printBattleShip(board1);
break;
} else {
System.out.println("PLAYER 2 HIT PLAYER 1's SHIP!");
}
} else if (board1[c][d] == '-') {
history2[c][d] = 'O';
board1[c][d] = 'O';
System.out.println("PLAYER 2 MISSED!");
}
} else {
System.out.println("You already fired on this spot. Choose different coordinates.");
}
} else {
System.out.println("Invalid coordinates. Choose different coordinates.");
}
}
} while (onGoing);
private static String check(char[][] arr1) {
int sum = 0;
for (int i = 0; i < arr1.length; i++) {
for (int j = 0; j < arr1.length; j++) {
if (arr1[i][j] == '#') {
sum += 1;
}
}
}
if (sum == 0) {
return "win";
} else {
return "keep playing";
}
}
// I declared and initialized a boolean variable called ongoing before a do-while loop. Then I create a while loop inside the do while loop. And inside the while loop, there are a series of conditional statement. Eventually, I changed the value of the boolean variable and feed it back to the while statement, letting it evaluate it. But it doesn't seem to change the value. Is it because the scope of the variable? How can I fix it?
edit: check method added

How to stop funciton looping? [duplicate]

This question already has answers here:
How do you stop a loop from running in Java
(3 answers)
Closed 4 years ago.
I'm working on a simple tic-tac-toe 4x4 game. I have input() function where user enters his data, printBoard() which prints the board itself, analyzeBoard() where are all the calculations for choosing the winner and done() which simply returns status. My problem is that even when I find the winner I can't stop input() working and it keeps printing board over and over. For the first time, I thought that problem is in analyzeBoard() but then I figured out that it actually returns everything I need and the problem is in input(). When I try to return from input, it either says missing return statement either just doesn't stop even though it can see the winner.
public char input ()
{
while (status == false || numberOfMovesLeft > 0)
{
System.out.println("User "+ whoseTurn + " enter your move: "); //prompt user to make a move
char userInput = reader.next().charAt(0); // local variable to hold user input
// validation of user input
while (userInput != 'a' && userInput != 'b' && userInput != 'c'
&& userInput != 'd' && userInput != 'e' && userInput != 'f'
&& userInput != 'g' && userInput != '1' && userInput != '2'
&& userInput != '3' && userInput != '5' && userInput != '6'
&& userInput != '6' && userInput != '7' && userInput != '8'
&& userInput != '9')
{
System.out.println("Try again, user "+ whoseTurn + " enter your move: ");
userInput = reader.next().charAt(0);
}
// places user input into a board cell
for (int row = 0; row < board.length; row++)
{
for (int col = 0; col < board[row].length; col++)
{
if (board[row][col] == userInput)
{
board[row][col] = whoseTurn;
}
}
}
// check for tie result
numberOfMovesLeft--;
if (numberOfMovesLeft==0)
{
System.out.println("Tie!");
winner = 'T';
System.out.println(winner);
}
analyzeBoard();
printBoard();
done();
whoseTurn = (whoseTurn == 'X') ? '0' : 'X';
}
return winner;
}
public void analyzeBoard()
{
// row winner algoritm
for (int row = 0; row <=3; row++)
{
for (int col = 0; col < 2; col++)
{
if (board[row][col] == board[row][col + 1]
&&
board[row][col] == board[row][col + 2])
{
System.out.println("winner");
winner = whoseTurn;
System.out.println("winner "+ winner);
System.out.println("whoseTurn "+ whoseTurn);
status = true;
System.out.println("status "+status);
done();
}
else
{
//System.out.println("status "+status);
}
}
}
//column winner algoritm
for (int row = 0; row <2; row++)
{
for (int col = 0; col <= 3; col++)
{
if (board[row][col] == board[row+1][col] &&
board[row][col] == board[row+2][col])
{
System.out.println("winner");
winner = whoseTurn;
System.out.println("winner "+ winner);
System.out.println("whoseTurn "+ whoseTurn);
status = true;
//System.out.println("status "+status);
}
}
}
//diagonal winner algoritm
for (int row = 0; row <2; row++)
{
for (int col = 0; col <2; col++)
{
if (board[row][col] == board[row+1][col+1] &&
board[row][col] == board[row+2][col+2])
{
System.out.println("winner");
winner = whoseTurn;
System.out.println("winner "+ winner);
System.out.println("whoseTurn "+ whoseTurn);
status = true;
//System.out.println("status "+status);
}
}
}
//diagonal winner algoritm
for (int row = 0; row <2; row++)
{
for (int col = 2; col <=3; col++)
{
if (board[row][col] == board[row+1][col-1])
{
System.out.println("winner");
winner = whoseTurn;
System.out.println("winner "+ winner);
System.out.println("whoseTurn "+ whoseTurn);
status = true;
//System.out.println("status "+status);
}
}
}
}
you can use break; to terminate current loop or return; to terminate entire function call.

Minimax algorithm in 4x4 TicTacToe board

I'm working in artificial intelligence project to develop a TicTacToe 4X4 using Minimax algorithm
I have this existing program that run Minimax algorithm in 3x3 TicTacToe board.
I want to extend it to 4x4 TicTacToe
but I couldn't any idea how I can do it ??
import java.util.*;
//defines the point where to place 1 or 2
class Point {
int x, y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
#Override
public String toString() {
return "[" + x + ", " + y + "]";
}
}
//defines the score per point -1,0,1
class PointsAndScores {
int score;
Point point;
PointsAndScores(int score, Point point) {
this.score = score;
this.point = point;
}
}
//defince the game board
class Board {
List<Point> availablePoints;
Scanner scan = new Scanner(System.in);
int[][] board = new int[3][3];
public Board() {
}
public boolean isGameOver() {
//Game is over is someone has won, or board is full (draw)
return (hasXWon() || hasOWon() || getAvailableStates().isEmpty());
}
//check if X have won represented by 1
public boolean hasXWon() {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 1) || (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 1)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < 3; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 1)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 1))) {
// System.out.println("O Row or Column win");
return true;
}
}
return false;
}
//check if O has won represented by 2
public boolean hasOWon() {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 2) || (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 2)) {
// System.out.println("X Diagonal Win");
return true;
}
for (int i = 0; i < 3; ++i) {
if ((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 2)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 2)) {
// System.out.println("X Row or Column win");
return true;
}
}
return false;
}
//check available states in the board
public List<Point> getAvailableStates() {
availablePoints = new ArrayList<>();
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
if (board[i][j] == 0) {
availablePoints.add(new Point(i, j));
}
}
}
return availablePoints;
}
//put player move in the board
public void placeAMove(Point point, int player) {
board[point.x][point.y] = player; //player = 1 for O, 2 for X..
}
//get best movement according to the board state
public Point returnBestMove() {
int MAX = -100000;
int best = -1;
for (int i = 0; i < rootsChildrenScores.size(); ++i) {
if (MAX < rootsChildrenScores.get(i).score) {
MAX = rootsChildrenScores.get(i).score;
best = i;
}
}
return rootsChildrenScores.get(best).point;
}
//accepts input from user
void takeHumanInput() {
System.out.println("Your move: ");
int x = scan.nextInt();
int y = scan.nextInt();
Point point = new Point(x, y);
placeAMove(point, 2);
}
//display current board
public void displayBoard() {
System.out.println();
for (int i = 0; i < 3; ++i) {
for (int j = 0; j < 3; ++j) {
System.out.print(board[i][j] + " ");
}
System.out.println();
}
}
//get min value
public int returnMin(List<Integer> list) {
int min = Integer.MAX_VALUE;
int index = -1;
for (int i = 0; i < list.size(); ++i) {
if (list.get(i) < min) {
min = list.get(i);
index = i;
}
}
return list.get(index);
}
//get max value
public int returnMax(List<Integer> list) {
int max = Integer.MIN_VALUE;
int index = -1;
for (int i = 0; i < list.size(); ++i) {
if (list.get(i) > max) {
max = list.get(i);
index = i;
}
}
return list.get(index);
}
//declares a list for scores
List<PointsAndScores> rootsChildrenScores;
//excutes minimax algorithm
public void callMinimax(int depth, int turn){
rootsChildrenScores = new ArrayList<>();
minimax(depth, turn);
}
//minimax algorithm
public int minimax(int depth, int turn) {
if (hasXWon()) return +1;
if (hasOWon()) return -1;
//get available states from the board
List<Point> pointsAvailable = getAvailableStates();
if (pointsAvailable.isEmpty()) return 0;
//stores scores
List<Integer> scores = new ArrayList<>();
for (int i = 0; i < pointsAvailable.size(); ++i) {
Point point = pointsAvailable.get(i);
if (turn == 1) { //O's turn select the highest from below minimax() call
placeAMove(point, 1);
int currentScore = minimax(depth + 1, 2);
scores.add(currentScore);//add scores to the list
if (depth == 0)
rootsChildrenScores.add(new PointsAndScores(currentScore, point));
} else if (turn == 2) {//X's turn select the lowest from below minimax() call
placeAMove(point, 2);
scores.add(minimax(depth + 1, 1));
}
board[point.x][point.y] = 0; //Reset this point
}
return turn == 1 ? returnMax(scores) : returnMin(scores);
}
}
//main class
public class TicTacToe {
public static void main(String[] args) {
Board b = new Board();//instantiate board
Random rand = new Random();//instantiate random value
b.displayBoard();//display board
System.out.println("Who's gonna move first? (1)Computer (2)User: ");
int choice = b.scan.nextInt();
if(choice == 1){
Point p = new Point(rand.nextInt(3), rand.nextInt(3));
b.placeAMove(p, 1);
b.displayBoard();
}
while (!b.isGameOver()) {
System.out.println("Your move: ");
Point userMove = new Point(b.scan.nextInt(), b.scan.nextInt());
b.placeAMove(userMove, 2); //2 for X and X is the user
b.displayBoard();
if (b.isGameOver()) {
break;
}
b.callMinimax(0, 1);
for (PointsAndScores pas : b.rootsChildrenScores) {
System.out.println("Point: " + pas.point + " Score: " + pas.score);
}
b.placeAMove(b.returnBestMove(), 1);
b.displayBoard();
}
if (b.hasXWon()) {
System.out.println("Unfortunately, you lost!");
} else if (b.hasOWon()) {
System.out.println("You win! This is not going to get printed.");
} else {
System.out.println("It's a draw!");
}
}
}
You need to introduce an integer variable, let's say n, which will contain the size of the board(i.e. # of cells = n*n). Before a game starts, the player will be asked for the preferred board size, 3 or 4, and the corresponding board will be created. In order for your program to work with 4x4 like it did with 3x3, we will need to place the variable n wherever we have a method or loop that needs to traverse through the board. In other words, instead of 3 we will place n. This will "generalize" our program. For example, within the display method we have 2 for loops that run as long as i and j are smaller than 3. To "generalize" our program to a semi-arbitrary board size(3 or 4), we place an n in place of the 3 so that the loop will run as long as i and j are smaller than n(3 or 4). This change from 3 to n will apply wherever we have a 3 that indicates the size of the board. Another thing we will need to change are the checking methods hasXWon() and hasOWon(). Here, we will need to add an extra section for when the board size is 4 and not 3. This will look more or less the same as it's counterpart with the only difference being that it will check the extra row, column and longer diagonals that exist in a 4x4 board. After inserting these changes, the program now looks like this:
import java.util.*;
//defines the point where to place 1 or 2
class Point {
int x, y;
public Point(int x, int y) {
this.x = x;
this.y = y;
}
#Override
public String toString() {
return "[" + x + ", " + y + "]";
}
}
//defines the score per point -1,0,1
class PointsAndScores {
int score;
Point point;
PointsAndScores(int score, Point point) {
this.score = score;
this.point = point;
}
}
//defince the game board
class board {
List<Point> availablePoints;
Scanner scan = new Scanner(System.in);
public int n;
int[][] board;
public board(int n) {
this.n = n;
board = new int[n][n];
}
public boolean isGameOver() {
//Game is over is someone has won, or board is full (draw)
return (hasXWon() || hasOWon() || getAvailableStates().isEmpty());
}
//check if X have won represented by 1
public boolean hasXWon() {
if(n==3){
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 1) || (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 1)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < n; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 1)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 1))) {
// System.out.println("O Row or Column win");
return true;
}
}
return false;
}
else {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == board[3][3]&& board[0][0] == 1) || (board[0][3] == board[1][2] && board[0][3] == board[2][1] && board[0][3] == board[3][0] && board[0][3] == 1)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < n; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 1)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 1))) {
// System.out.println("O Row or Column win");
return true;
}
}
return false;
}
}
//check if O has won represented by 2
public boolean hasOWon() {
if(n==3){
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == 2) || (board[0][2] == board[1][1] && board[0][2] == board[2][0] && board[0][2] == 2)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < n; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 2)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 2))) {
// System.out.println("O Row or Column win");
return true;
}
}
return false;
}
else {
if ((board[0][0] == board[1][1] && board[0][0] == board[2][2] && board[0][0] == board[3][3]&& board[0][0] == 2) || (board[0][3] == board[1][2] && board[0][3] == board[2][1] && board[0][3] == board[3][0] && board[0][3] == 2)) {
//System.out.println("O Diagonal Win");
return true;
}
for (int i = 0; i < n; ++i) {
if (((board[i][0] == board[i][1] && board[i][0] == board[i][2] && board[i][0] == 2)
|| (board[0][i] == board[1][i] && board[0][i] == board[2][i] && board[0][i] == 2))) {
// System.out.println("O Row or Column win");
return true;
}
}
return false;
}
}
//check available states in the board
public List<Point> getAvailableStates() {
availablePoints = new ArrayList<>();
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
if (board[i][j] == 0) {
availablePoints.add(new Point(i, j));
}
}
}
return availablePoints;
}
//put player move in the board
public void placeAMove(Point point, int player) {
board[point.x][point.y] = player; //player = 1 for O, 2 for X..
}
//get best movement according to the board state
public Point returnBestMove() {
int MAX = -100000;
int best = -1;
for (int i = 0; i < rootsChildrenScores.size(); ++i) {
if (MAX < rootsChildrenScores.get(i).score) {
MAX = rootsChildrenScores.get(i).score;
best = i;
}
}
return rootsChildrenScores.get(best).point;
}
//accepts input from user
void takeHumanInput() {
System.out.println("Your move: ");
int x = scan.nextInt();
int y = scan.nextInt();
Point point = new Point(x, y);
placeAMove(point, 2);
}
//display current board
public void displayboard() {
System.out.println();
for (int i = 0; i < n; ++i) {
for (int j = 0; j < n; ++j) {
System.out.print(board[i][j] + " ");
}
System.out.println();
}
}
//get min value
public int returnMin(List<Integer> list) {
int min = Integer.MAX_VALUE;
int index = -1;
for (int i = 0; i < list.size(); ++i) {
if (list.get(i) < min) {
min = list.get(i);
index = i;
}
}
return list.get(index);
}
//get max value
public int returnMax(List<Integer> list) {
int max = Integer.MIN_VALUE;
int index = -1;
for (int i = 0; i < list.size(); ++i) {
if (list.get(i) > max) {
max = list.get(i);
index = i;
}
}
return list.get(index);
}
//declares a list for scores
List<PointsAndScores> rootsChildrenScores;
//excutes minimax algorithm
public void callMinimax(int depth, int turn){
rootsChildrenScores = new ArrayList<>();
minimax(depth, turn);
}
//minimax algorithm
public int minimax(int depth, int turn) {
if (hasXWon()) return +1;
if (hasOWon()) return -1;
//get available states from the board
List<Point> pointsAvailable = getAvailableStates();
if (pointsAvailable.isEmpty()) return 0;
//stores scores
List<Integer> scores = new ArrayList<>();
for (int i = 0; i < pointsAvailable.size(); ++i) {
Point point = pointsAvailable.get(i);
if (turn == 1) { //O's turn select the highest from below minimax() call
placeAMove(point, 1);
int currentScore = minimax(depth + 1, 2);
scores.add(currentScore);//add scores to the list
if (depth == 0)
rootsChildrenScores.add(new PointsAndScores(currentScore, point));
} else if (turn == 2) {//X's turn select the lowest from below minimax() call
placeAMove(point, 2);
scores.add(minimax(depth + 1, 1));
}
board[point.x][point.y] = 0; //Reset this point
}
return turn == 1 ? returnMax(scores) : returnMin(scores);
}
}
//main class
public class TicTacToe {
public static void main(String[] args) {
//board b = new board();//instantiate board
Random rand = new Random();//instantiate random value
Point p;
Scanner s = new Scanner(System.in);
System.out.println("Choose board size: 3 or 4?");
int n=s.nextInt();
board b = new board(n); //Instantiating board after value of n has been read. This is important because the value of n is required for the instantiation to take place.
System.out.println(b.n);
b.displayboard();//display board
System.out.println("Who's gonna move first? (1)Computer (2)User: ");
int choice = b.scan.nextInt();
if(choice == 1){
if(b.n==3)
p = new Point(rand.nextInt(3), rand.nextInt(3));
else
p = new Point(rand.nextInt(4), rand.nextInt(4));
b.placeAMove(p, 1);
b.displayboard();
}
while (!b.isGameOver()) {
System.out.println("Your move: ");
Point userMove = new Point(b.scan.nextInt(), b.scan.nextInt());
b.placeAMove(userMove, 2); //2 for X and X is the user
b.displayboard();
if (b.isGameOver()) {
break;
}
b.callMinimax(0, 1);
for (PointsAndScores pas : b.rootsChildrenScores) {
System.out.println("Point: " + pas.point + " Score: " + pas.score);
}
b.placeAMove(b.returnBestMove(), 1);
b.displayboard();
}
if (b.hasXWon()) {
System.out.println("Unfortunately, you lost!");
} else if (b.hasOWon()) {
System.out.println("You win! This is not going to get printed.");
} else {
System.out.println("It's a draw!");
}
}
}
Your program is now able to create 4x4 games. There are however two things that you need to do. First, your placeAMove(...) method doesn't check if a cell is occupied before filling it. This may lead to cells being overwritten, so you must change that by checking if a cell is occupied before trying to fill it. The second and more important thing is that although the program is now able to create 4x4 games, it will not be able to carryout a proper game. The reason for this is that the number of nodes(states) created by minimax to find the next move, although manageable in 3x3 games, rises dramatically for 4x4 games. This means that it would take your computer A LOT of time, and by a lot I mean hours, to calculate the computer's second move. Even when I rigged the game(i.e. manually inserted random 1s and 2s in the cells before allowing minimax to be called to choose the computer's move) it still took the computer over 30 seconds to calculate it's move. This renders your game, of course, unplayable in 4x4 mode. There are, of course, ways, such as Memoization or Alpha-Beta Pruning or both together, to overcome this and speed up your algorithm. Here is a previously asked question to get you started on these topics. The chess programming wiki is also a good source of information on such topics, if a bit more complex in it's structure. Here's their entry on Memoization(Here called transposition tables).

Tic Tac Toe java draw game

So I did a Tic Tac Toe assignment for my class. I have successfully created a simple Tic Tac Toe program but somehow the method to check for draw sometimes doesn't come out right. If everything is filled but there's no winner, then it's a draw. But if everything else is filled except for row 0 column 1, it will still show "draw" even if that box is still blank. If you don't get what I mean, just try filling out everything but the middle box on the top row but don't win, it will say "draw" even though that last box is not filled. What did I do wrong in my code???? Here's the driver:
import javax.swing.JOptionPane;
public class TwoDimensionalArray_Driverr
{
public static void main(String[]args)
{
char player = 'o';
TwoDimensionalArrayy game = new TwoDimensionalArrayy();
while (game.checkGame() == "PLAY")
{
if (player == 'o') player = 'x';
else player = 'o';
System.out.println(game);
String input = JOptionPane.showInputDialog("Enter Position of Row for player "+ player +" or press Cancel to exit");
if (input == null)
System.exit(0);
int row = Integer.parseInt(input);
input = JOptionPane.showInputDialog("Enter Position of Column for player " + player);
int column = Integer.parseInt(input);
game.set(row,column,player);
game.isDraw();
game.hasWon(row,column,player);
game.checkGame();
System.out.println(game.checkGame());
}
if (game.checkGame()=="DRAW"){
System.out.println(game);
System.out.println("It's a draw.");
}
else {
System.out.println(game);
System.out.println(player + " has won.");}
}
}
And here is the Object:
public class TwoDimensionalArrayy
{
private String currentState = "GO";
private char[][] board;
private static final int ROWS = 3;
private static final int COLUMNS = 3;
public TwoDimensionalArrayy(){
board = new char[ROWS][COLUMNS];
for(int i=0;i<ROWS;i++) //always do ROWS first!!!!
for(int j = 0;j<COLUMNS;j++)
board[i][j]=' ';
}
public void set(int i, int j, char player)
{
if(board[i][j] != ' ' )
throw new IllegalArgumentException("Position Occupied");
board[i][j] = player;
}
public String toString()
{
System.out.println("This is the board. 3x3");
System.out.println("Position start # row[0]col[0],row[0]col[1],row[0]col[2]");
String dString= "";
for (int row = 0; row<ROWS; row++)
{
if (COLUMNS>0)
dString += board[row][0];
for (int col = 1; col<COLUMNS; col++)
{
dString+= "|" + board[row][col];
} //end 2nd for
dString += "\n";
}//end first for
return dString;
}
public String checkGame(){
if (currentState=="Win"){
return "END";}
else if (currentState=="Draw"){
return "DRAW";}
else return "PLAY";
}
public void hasWon(int i,int j,char player){
if (board[i][0] == player // 3-in-the-row
&& board[i][1] == player
&& board[i][2] == player
|| board[0][j] == player // 3-in-the-column
&& board[1][j] == player
&& board[2][j] == player
|| i == j // 3-in-the-diagonal
&& board[0][0] == player
&& board[1][1] == player
&& board[2][2] == player
|| i + j == 2 // 3-in-the-opposite-diagonal
&& board[0][2] == player
&& board[1][1] == player
&& board[2][0] == player)
currentState = "Win";
}
public void isDraw(){
for ( int row = 0; row < ROWS; row++) {
for (int col = 0; col < COLUMNS; col++) {
if (board[row][col] == ' ') {
currentState = "Play";
break;
}
else {currentState = "Draw";} // no empty cell, it's a draw}
}
}
}
}
public void isDraw(){
for ( int row = 0; row < ROWS; row++) {
for (int col = 0; col < COLUMNS; col++) {
if (board[row][col] == ' ') {
currentState = "Play";
break;
} else {
currentState = "Draw"; // no empty cell, it's a draw
}
}
}
}
The break here will escape the inner for loop, but not the outer one. Essentially isDraw only considers the last row. You should try using return instead.

SOS Game: Concept of Tic-Tac-Toe

I am creating a game called SOS. It is a 3x3 board game and it has the same concept as Tic-Tac-Toe but in this game, the players cannot choose whether they will play as X or O, the only rule in this game is to form "SOS".
Our program should be terminated after all the positions are filled, and each formed "SOS" will be added to the player who formed "SOS".
My problem is about scoring. After entering SOS in the first row which is (- - -), I tried to input "O" in the second row first column, and the player 2 will increment. It should not increment because it didn't satisfy the second else if in my program. Why is it happening?
Here is my code:
import java.util.Scanner;
public class SOS
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
String ar[] = {"-","-","-","-","-","-","-","-","-"};
int player1 = 0;
int player2 = 0;
int index = 0;
for(int l = 0; l<3; l++)
{
for(int j = 0; j<3; j++)
{
System.out.print(ar[j]);
}
System.out.print("\n");
}
for(int j = 0;j < 9;j++)
{
//Input position and letter
System.out.println("Enter the position number: ");
index = input.nextInt();
input.nextLine();
System.out.println("Enter (S or O): ");
ar[index - 1] = input.nextLine();
//Output for the game
for(int l = 0; l<9; l++)
{
System.out.print(ar[l]);
if(l == 2)
{
System.out.println();
}
else if(l == 5)
{
System.out.println();
}
else if(l == 8)
{
System.out.println();
}
}
//condition
if((ar[0]+ar[1]+ar[2]).equals("SOS"))
{
if(j%2 == 0)
{
player1++;
System.out.println("Player 1: "+player1+" Player 2: "+player2);
}
else if( j % 2 != 0)
{
player2++;
System.out.println("Player 1: "+player1+" Player 2: "+player2);
}
}
else if((ar[3]+ar[4]+ar[5]).equals("SOS"))
{
if(j%2 == 0)
{
player1++;
System.out.println("Player 1: "+player1+" Player 2: "+player2);
}
else if( j % 2 != 0)
{
player2++;
System.out.println("Player 1: "+player1+" Player 2: "+player2);
}
}
else
{
System.out.println("Player 1: "+player1+" Player 2: "+player2);
}
//end of condition
}
}
}
The bug is occurring in this section of your code:
if((ar[0]+ar[1]+ar[2]).equals("SOS"))
After the first player correctly enters SOS into these positions, this statement will always be true. Which means that your nested if/else is running on every turn:
if(j%2 == 0)
{
player1++;
}
else if( j % 2 != 0)
{
player2++;
}
During the 4th turn, j will be equal to 3. (j%2 != 0) is true, which increments player2.
If you continue running the program, you will see player1 and player2 continually incrementing on every turn because the initial if will always be true.

Categories