Java TicTacToe game does not display correctly

Question

OK, so I'm writing a game of Tic Tac Toe. I've got the whole program written, but I can't understand why it's not displaying correctly?

import java.util.Scanner;

public class TicTacToeGame {

        //constants for game options
        static final int STANDARD_GAME = 0;
    static final int QUIT = -1;

    //constants for the number of rows and columns in a standard TicTacToe grid
    static final int STANDARD_GRID_ROWS = 3;
    static final int STANDARD_GRID_COLUMNS = 3;

    //two dimensional array to represent a TicTacToe grid
    static char[][]grid = new char[STANDARD_GRID_ROWS][STANDARD_GRID_COLUMNS];

    //Scanner for input
    static Scanner keyboard = new Scanner(System.in);

//***RUN STANDARD GAME******************************************************

    static void runStandardGame() {

        int position = QUIT;
        char playerChar = 'X';
        boolean isGameOver = false;

        fillPosition();

        System.out.println("Choose a position to play.\n");

        displayGrid();

        do {
            System.out.print("Player " + playerChar +
             " (Enter a position or " + QUIT + " to resign): ");
            position = keyboard.nextInt();

            System.out.println("Choose a position to play.\n");

            displayGrid();

            if(isWin()) {
                System.out.print("\nPlayer " + playerChar +"WINS!!!\n");
                isGameOver = true;
            }
            else if (isTie()) {
                System.out.print("\nTIE.\n");
                isGameOver = true;
            }
            else {
                //switch players because one of the players has just played
                //and not won;, so, it is the other player's turn
                if (playerChar == 'X') {
                    playerChar = 'O';
                }
                else{
                    playerChar = 'X';
                }
            }
           }while(!isGameOver && position != QUIT);

    }//end of runStandardGame

//***PLAY*******************************************************************    

    static void play(int cell, char playerChar) {
        //the player has entered a number 1 through 9 for the position they want
        //to play, so, figure out which row and which column of the array this     is
        //For example, if the player wants to play 'X' in position 7, this means
        //the 'X' must go into row 2, column 0 of the array
        int row = 0;
        int column = 0;

        if (cell > 0 && cell <= (STANDARD_GRID_ROWS * STANDARD_GRID_COLUMNS)){
            row = (cell - 1) / STANDARD_GRID_ROWS;
            column = (cell - 1) % STANDARD_GRID_COLUMNS;
            grid[row][column] = playerChar;
        }
    }

//***IS WIN*****************************************************************    

    static boolean isWin() {
        boolean isWin = false;

        if (isRowWin() || isColumnWin() || isDiagonalWin()){
            isWin = true;
        }

        return isWin;
    }

//***IS TIE*****************************************************************

    static boolean isTie() {
        boolean isTie = false;

                if(!isRowWin() || !isColumnWin() || !isDiagonalWin()){

        int count = 9;                   

        for (int row = 0; row < 3; row ++){

            for (int column = 0; column < 3; column ++){
                if (grid[row][column] == 0)
                    count --;
                }
        }

        if (count == 0)
            {
            System.out.println("\nSorry, this game is tied.  Better luck next time!");
            return true;                
            }
        }
        return isTie;
    }

//***IS ROW WIN**********************************************************

    static boolean isRowWin() {

        boolean isRowWin = false;
        int column = 0 ;

        for (int row = 0;row < STANDARD_GRID_ROWS && !isRowWin; row++) {

            //if the three array elements on the same row are equal, 
            //then one of the players has either three 'X's on that
            //row, or three 'O's, and therefore, has won
            if (grid[row][column] == grid[row][column+1] &&
                grid[row][column+1] == grid[row][column+2]){
                    isRowWin = true;
                }
        }

        return isRowWin;

    }

//***IS COLUMN WIN**********************************************************

    static boolean isColumnWin() {

        boolean isColumnWin = false;

        int row = 0 ;

        for (int column = 0;column < STANDARD_GRID_COLUMNS && !isColumnWin;      column++) {

            //if the three array elements on the same row are equal, 
            //then one of the players has either three 'X's on that
            //row, or three 'O's, and therefore, has won
            if (grid[row][column] == grid[row+1][column] &&
                grid[row+1][column] == grid[row+2][column]){
                    isColumnWin = true;
                }
        }

        return isColumnWin;

    }

//***IS DIAGONAL WIN********************************************************

    static boolean isDiagonalWin() {

        boolean isDiagonalWin = false;
        int row = 0;
        int column = 0;
        if(
                (grid[row][column] == grid[row+1][column+1] &&
            grid[row+1][column+1] == grid[row+2][column+2])||
            (grid[row][column+2] == grid[row+1][column+1] &&
            grid[row+1][column+1] == grid[row+2][column])){
                isDiagonalWin = true;
            }

        return isDiagonalWin;

    }

//***GET USER CHOICE********************************************************

    static int getUserChoice() {
        int choice;

        System.out.print("Please enter your choice: ");
        choice = keyboard.nextInt();

        return choice;

    }

//***FILL POSITIONS*********************************************************

    static void fillPosition(){

        char position = '1';

                for (int row = 0; row < STANDARD_GRID_ROWS; row++) {
                    for (int column = 0; column < STANDARD_GRID_COLUMNS; column++) {
                         grid[row][column] = (char) ('1' + row*STANDARD_GRID_COLUMNS + column);
                    }
                }

        }

//***DISPLAY GRID***********************************************************

    static void displayGrid() {



    System.out.println((grid[0][0]) + " | " + (grid[0][1]) + " | " + (grid[0][2]));
    System.out.println("---------");
    System.out.println((grid[1][0]) + " | " + (grid[1][1]) + " | " + (grid[1][2]));
    System.out.println("---------");
    System.out.println((grid[2][0]) + " | " + (grid[2][1]) + " | " + (grid[2][2]));


    }

//***END********************************************************************

}//end of class

In the game, I want it to display the board as:

 1 | 2 | 3
-----------
 4 | 5 | 6
-----------
 7 | 8 | 9

Regardless of what I choose, or where, it repeatedly ask me to make a choice...Even though I will purposely make one win, or make them tie to get it to end, it's neverending...is that a logical error?

ALSO, I deleted some of the code that I know is correct so it will be easier to read and understand.

Answer 1

The do-while loop in fillPosition only gets executed once. In the condition row<4 && column<4 && position<10, the boolean position<10 will initially be false. Because position is a char,

position < 10

is interpreted as

(int)position < 10

(int)position = (int)'2' = 49 (position is '2' after the first loop iteration), which is not less than 10, so this condition is false, meaning the entire loop-condition is also false - and hence the loop ends.

So, the '1' gets placed correctly but nothing else does (it's a do-while loop, so it executes at least once regardless of its condition).

Answer 2

You're fillPosition do-loop's exit condition is wrong...

I'd also advise against using character arithmetic, better to use an int and Interger.toString(int), but that's just me.

Take a loop at using compound for loops to fill the grid array, the outer begin used for the rows and the inner for the columns, for example

Answer 3

You are trying to compare a char (column) with 10 which is a number, the ascii number for the character '1' is bigger than then, so the loop is breaking

Answer 4

Your fillPosition() method is not correct. It should look sth like this:

    static void fillPosition(){
        for (int row = 0; row < STANDARD_GRID_ROWS; row++) {
            for (int column = 0; column < STANDARD_GRID_COLUMNS; column++) {
                grid[row][column] = (char) ('1' + row*STANDARD_GRID_COLUMNS + column);
            }
        }

    }