/*
* This is a program for Tic-Tac-Toe. The board
* is represented by a 2-D array.
*
*/

import java.util.*;
public class TicTacToe
{
  static char[][] board;
  public static void main(String[] args) throws java.io.IOException
  {
    initialize();
    char_player = 'X';
    while(game_not_over())
    {
      player_moves(player);
      player = other_player(player);
      print_board();
    }
    print_winner();
  }
  
  static void initialize()
  {
    board = new char[3][3];
    for(int row = 0; row < 3; row++)
    {
       for(int column = 0; column < 3; column++)
       {
         board[row][column] = '_';
       }
    }
  }
  
  static boolean game_not_over()
  {
    boolean a_winner;
    
    a_winner = win('X');
    if(a_winner) return false;
    a_winner = win('0');
    if(a_winner) return false;
    
    int count_moves = 0;
    for(int row = 0; row < 3; row++)
    {
      int three_in_a_row = 0;
      for(int column = 0; column < 3; column++)
      {
        if(board[row][column] != '_') count_moves++;
      }
    }
    if(count_moves == 9) return false;
    return true;
  }
  
  static void player_moves(char player) throws java.io.IOException
  {
    Scanner s = new Scanner(System.in);
    
    int move = 0;
    boolean move_ok = false;
    while(! move_ok)
    {
      System.out.println("Enter position for next "+player+" move");
      move = s.nextInt();
      move_ok = ok_move(move);
    }
    mark(move.player);
  }
  
  static char other_player(char player)
  {
    if(player == 'X') return 'O';
    else return 'X';
  }
  static void print_board()
  {
    for(int row = 0; row < 3; row++)
    {
      for(int column = 0; column < 3; column++)
      {
        System.out.print(board[row][column]+" ");
      }
      System.out.println();
    }
  }
  
  static void print_winner()
  {
    if(win('X')) System.out.println("X is the winner");
    else if(win('O')) System.out.println("O  is the winner");
    else System.out.println("I guess that cat won.");
  }
  
  static boolean win(char xo)
  {
    if(board[0][0]== xo && board[0][1] == xo && board[0][2] == xo)
      return true;
    if(board[1][0] == xo && board[1][1] == xo && board[1][2] == xo)
      return true;
    if(board[2][0]== xo && board[2][1] == xo && board[2][2] == xo)
      return true;
    
    if(board[0][0] == xo && board[1][0] == xo && board[2][0] == xo)
      return true;
    if(board[0][1] == xo && board[1][1] == xo && board[2][1] == xo)
      return true;
    if(board[0][2] == xo && board[1][2] == xo && board[2][1] == xo)
      return true;
    
    if(board[0][0] == xo && board[1][1] == xo && board[2][2] == xo)
      return true;
    if(board[0][2] == xo && board[1][1] == xo && board[2][0] == xo)
      return true;
     return false;
     }
    
  
  static void mark(int position, char x_or_o)
  {
    int row = (position-1)/3;
    int column = (position-1)%3;
    board[row][column] = x_or_o;
  }
  }
        
    
    
      
  
      
  
        

  public static void main(String[] args) throws java.io.IOException
  {
    initialize();
    char_player = 'X';

   char player = 'X';

public class TicTacToe
{
  static char[][] board;
  public static void main(String[] args)
  {
    initialize();
    char player = 'X';
    while(inGame())
    {
      player_moves(player);
      player = switch_player(player);
      print_board();
    }
    print_winner();
  }
  
  void initialize()
  {
     board = new char[3][3];
     for(int i = 0; i< 3; i++)
     {
        for(int j = 0; j < 3; j++)
        {
          board[i][j] = '_';
        }
     }
  }
  
  boolean inGame()
  {
    boolean winner;
    winner = win('X');
    if(winner)
      return false;
    winner = win('O');
    if(winner)
      return false;
  
    int count = 0;
    for(int i = 0; i < 3; i++)
    {
      int three_in_a_row = 0;
      for(int j = 0; j < 3; j++)
      {
        if(board[i][j] != '_')
        count++;
      }
    }
    if(count == 9)
      return false;
      return true;
  }
  
  void player_moves(char player)
  {
     Scanner s = new Scanner(System.in);
     int move = 0;
     boolean move_legal = false;
     while(! move_legal)
     {
       System.out.println("Enter number for next " +player+ "move.");
       move = s.nextInt();
       move_legal = legal_move(move);
     }
     draw(move,player);
  }
  
  char switch_player(char player)
  {
     if(player == 'X')
       return 'O';
     else
       return 'X';
  }
  
   void print_board()
  {
    for(int i = 0; i < 3; i++)
    {
      for(int j = 0; j < 3; j++)
      {
        System.out.println(board[i][j] + " ");
      }
      System.out.println();
    }
  }
  
  void print_winner()
  {
    if(win('X'))
    System.out.println("X is the winner");
    
    else if(win('O'))
    System.out.println("O is the winner");
    
    else
    System.out.println("No winner");
  }
  
  boolean win(char c)
  {
    if(board[0][0] == c && board[0][1] == c && board[0][2] == c)
      return true;
    
    if(board[1][0] == c && board [1][1] == c && board[1][2] == c)
      return true;
    
    if(board[2][0] == c && board[2][1] == c && board[2][2] == c)
      return true;
    
    if(board[0][0] == c && board[1][0] == c && board[2][0] == c)
      return true;
    
    if(board[0][1] == c && board[1][1] == c && board[2][1] == c)
      return true;
    
    if(board[0][2] == c && board[1][2] == c && board[2][2] == c)
      return true;
    
    if(board[0][0] == c && board[1][1] == c && board[2][2] == c)
      return true;
    
    if(board[0][2] == c && board[1][1] == c && board[2][0] == c)
      return true;
    return false;
    
  boolean legal_move(int position)
  {
    if(position < 1 || position > 9)
    {
       System.out.println("Error: invalid position" + position);
       return false;
    }
    else
    {
      int i = (position - 1)/3;
      int j = (position -1)%3;
      if(board[i][j] != '_')
      {
        System.out.println("You can't move here. The square is occupied.");
        return false;
      }
      return true;
    }
  }
  
  void draw(int position, char c)
  {
    int i = (position - 1)/3;
    int j = (position - 1)%3;
    board[i][j] = c;
  }
  }
}