I am writing a tic tac toe game for my class. Everything is working but I am unable to figure out how to make my computer player choose only spaces that are available. My code is glitching and allowing the computer to choose either the other players spaces or not playing at all. Any help will be appreciated.
import java.util.Random;
import java.util.Scanner;
public class TicTacToe1 {
public static void main(String[] args) {
welcome();
initializeBoard();
printBoard();
while ((!checkWin()) && (!checkDraw())) {
playerMove();
printBoard();
System.out.println();
computerMove();
printBoard();
}
System.out.println();
if (checkWin() == true) {
System.out.println("The winner is " + currentTurn);
}
if (checkDraw() == true) {
System.out.println("Draw");
}
}
private static String[][] board = new String[3][3];
private static int row, column;
public static Scanner scan = new Scanner(System.in);
public static String currentTurn = "X";
// public static String computerTurn = "O";
public static String turn() {
if (currentTurn == "X") {
currentTurn = "O";
} else {
currentTurn = "X";
}
return currentTurn;
}
private static void welcome() {
System.out.println("Tic Tac Toe");
System.out.println("Please enter your coordinates for your location row (1-3) column (1-3):");
}
public static void initializeBoard() { // initialize tic tac toe
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board.length; j++) {
board[i][j] = "-";
}
}
}
public static void printBoard() {
for (int i = 0; i < board.length; i++) {
System.out.println();
for (int j = 0; j < board.length; j++) {
if (j == 0) {
System.out.print("| ");
}
System.out.print(board[i][j] + " | ");
}
}
}
public static void playerMove() {
System.out.println();
System.out.println("Your Move: ");
row = scan.nextInt() - 1;
column = scan.nextInt() - 1;
if (board[row][column] == "-") {
board[row][column] = turn();
} else {
System.out.println("Invalid entry. Please go again");
row = scan.nextInt() - 1;
column = scan.nextInt() - 1;
board[row][column] = turn();
}
}
// public static void computerMove() {
// Random computerMove = new Random();
// row = computerMove.nextInt(3);
// column = computerMove.nextInt(3);
// if (board[row][column] == "-") {
// board[row][column] = turn();
// } else {
// }
// }
public static void computerMove() {
Random computerMove = new Random();
row = computerMove.nextInt(3);
column = computerMove.nextInt(3);
while (board[row][column] != "-") {
// Random computerMove = new Random();
// row = computerMove.nextInt(3);
// column = computerMove.nextInt(3);
if (board[row][column] == "-") {
board[row][column] = turn();
} else {
row = computerMove.nextInt(3);
column = computerMove.nextInt(3);
board[row][column] = turn();
}
}
}
public static boolean checkWin() {
return (checkDiagonalWin() || checkHorizontalWin() || checkVerticalWin());
}
public static boolean checkDiagonalWin() {
if ((board[0][0] == board[1][1]) && (board[0][0] == board[2][2]) && (board[1][1] != "-")) {
return true;
}
if ((board[0][2] == board[1][1]) && (board[0][2] == board[2][0]) && (board[1][1] != "-")) {
return true;
}
return false;
}
public static boolean checkHorizontalWin() {
// for (int i = 0; i < board.length; i++) {
if ((board[0][0] == board[0][1]) && (board[0][0] == board[0][2]) && (board[0][0] != "-")) {
return true;
}
if ((board[1][0] == board[1][1]) && (board[1][0] == board[1][2]) && (board[1][0] != "-")) {
return true;
}
if ((board[2][0] == board[2][1]) && (board[2][0] == board[2][2]) && (board[2][0] != "-")) {
return true;
}
// }
return false;
}
public static boolean checkVerticalWin() {
// for (int j = 0; j < board.length; j++) {
if ((board[0][0] == board[1][0]) && (board[0][0] == board[2][0]) && (board[0][0] != "-")) {
return true;
}
if ((board[0][1] == board[1][1]) && (board[0][1] == board[2][1]) && (board[0][1] != "-")) {
return true;
}
if ((board[0][2] == board[1][2]) && (board[0][2] == board[2][2]) && (board[0][2] != "-")) {
return true;
}
// }
return false;
}
public static boolean checkDraw() {
for (int i = 0; i < board.length; i++) {
for (int j = 0; j < board.length; j++) {
if (board[i][j] == "-") {
return false;
}
}
}
return true;
}
}
The issue was in your computerMove logic.
public static void computerMove() {
Random computerMove = new Random();
row = computerMove.nextInt(3);
column = computerMove.nextInt(3);
while (board[row][column] != "-") {
row = computerMove.nextInt(3);
column = computerMove.nextInt(3);
}
board[row][column] = turn();
}
This should work for you, just copy paste this in place of your computerMove.
Now as to why your code didn't work:- Your code:
while (board[row][column] != "-") {
if (board[row][column] == "-") {
board[row][column] = turn();
} else {
row = computerMove.nextInt(3);
column = computerMove.nextInt(3);
board[row][column] = turn();
}
}
The while loop looks at the position and sees that there is no '-', thus runs. Then inside your while loop you have a if statement which checks to see whether you have '-' at that position. That can never be true, because our while loop wouldn't run otherwise.
The best idea is to let your code keep changing the row and columns until you get a position with '-', and use your while loop to do that. As soon as you get the '-', your while loop won't run anymore anyways, so you can just set the board[row][columns] = turn() just outside the while loop, and your code will work fine.
P.S. Took a lot of willpower to not make a machines are uprising reference to your
My code is glitching and allowing the computer to choose either the other players spaces or not playing at all
Have fun with your program :)
~HelpfulStackoverflowCommunity