Calling methods and returning values? Tic-tac-toe

Question

I'm having problems getting my displayWinner method to work. I believe my calls aren't working in the way I think they should because I'm not very familiar with using multiple methods as this concept was only recently introduced.

The code is the following:

import java.util.*;
public class tic
{
    public static void main(String[] args) 
    {
        Scanner in = new Scanner(System.in);

        boolean flag=false;

        char[][] board = 
        {
        {' ', ' ', ' '},
        {' ', ' ', ' '},
        {' ', ' ', ' '}
        };

        boolean done = false;
        int player = 1;
        int row = 0;
        int col = 0;

        while (flag != true) 
        {
          checkForWinner(board);
          System.out.println("Enter the row and column for your next move");
          row = in.nextInt();
          col = in.nextInt();
          if (player == 1) 
          {
            board[row][col] = 'X';
            player = 2;
            checkForWinner(board);
           }
          else 
          { 
            board[row][col] = 'O';
            player = 1;
            checkForWinner(board);
          }
          printBoard(board);
          checkForWinner(board);
        }

        displayWinner(player, flag);  


    }
    public static void printBoard(char[][] board) 
    {
    for (int row = 0; row < 3; row++) 
    {
        for (int col = 0; col < 3; col++) 
        {
            System.out.print("|" + board[row][col] + "|");
        }
        System.out.println();
        System.out.println("-------");
    }
    }
    public static boolean checkForWinner(char[][] board)
   {
       // checkForWinner() method determines if a pattern of data stored
       // in the 2 D char array indicates the a player has won the game.

        boolean flag = false;
        boolean flag1 = false;
        boolean flag2 = false;
        boolean flag3 = false;
        boolean flag4 = false;

        // checks the contents of each row for matching data   
        for (int i = 0; i <= 2; i++)
        {
            if ((board[i][0] == board[i][1] && board[i][1] == board[i][2]) && board[i][2] != ' ') 
                flag1 = true;
        }

         // checks the contents of each column for matching data
        for (int j = 0; j <= 2; j++)
        {
            if ((board[0][j] == board[1][j] && board[1][j] == board[2][j]) && board[2][j] != ' ') 
                flag2 = true;
        }

        // checks the contents of one diagonal for matching data
        if ((board[0][0] == board[1][1] && board[1][1] == board[2][2]) && board[2][2] != ' ') 
                flag3 = true;

        // checks the contents of the other diagonal for matching data
        if ((board[0][2] == board[1][1] && board[1][1] == board[2][0]) && board[2][0] != ' ') 
                flag4 = true;

        // checks if any of the previous conditions evaluated to true        
        if (flag1 == true || flag2 == true || flag3 == true || flag4 == true)
            flag = true;

       // returns true if a winner was found; returns false is no winner     
       return flag;
   } // end of checkForWinner method
   public static void displayWinner(int player, boolean flag)
   {

    if (flag == true)
    {
        int currentplayer;
        currentplayer=player;
        System.out.println("The winner of the game is" +currentplayer);
    }


   }
}

The displayWinner method is at the bottom and the while loop in the main method is the one that plays the game and gives each player their turn.

Edit: My question would be how do I pass the flag from the checkForWinner method to the displayWinner method so that it can print out who the winner of the game is?

Answer 1

You are not updating flag declared in your main method. Change each of

checkForWinner(board);

to

flag = checkForWinner(board);

Without this flag will never change and you will never leave your while (flag != true) (which could be simplified to while(!flag)) loop which means you will never execute displayWinner(player, flag) method.