Simple TicTacToe Program

Question

Hi,
I'm taking an introductory Java class, and I'm just trying to complete an assignment in my textbook. Here is a copy of the code that I'm having a problem with:
import java.util.Scanner;
public class TicTacToeClient
     public static void main( String [] args )
          Scanner scan = new Scanner( System.in );
          TicTacToe ttt1 = new TicTacToe( );
          String garbage;
          int player = 1;
          boolean gameOver = false;
          int position;
          while ( ! gameOver )
               System.out.print( "Please enter a position, player " + player + " > " );
               while( ! scan.hasNextInt( ) )
                    garbage = scan.nextLine( );
                    System.out.print( "Please enter a valid position, player " + player + " > " );
               position = scan.nextInt( );
               if ( ! ttt1.isLegal( position ) )
                    System.out.println( "This position is already used!" );
               else
                    ttt1.makeMove( player, position );
                    if ( ttt1.gameWon( player ) || ttt1.isTie( ) )
                         gameOver = true;
                    else
                         if ( player == 1 )
                              player = 2;
                         else
                              player = 1;
          ttt1.printWinner( player );
I'm very sorry if the format of this code is hard to read, as the message textbox is pretty small.
Anyhow, when I enter 0 for player 1, and then an invalid character for player 2 ( such as 'j' ), I get the "Please enter a valid value ..." message twice in a row. I thought that the scan.hasNextInt( ) condition in the while loop would wait for the user to press Enter before repeating the loop. Why does this happen and how can I correct it?
Thanks in advance for your help.
Message was edited by:
invinciBill

Answer 1

Thanks for the link.
This should be easier to read:
import java.util.Scanner;
public class TicTacToeClient
     public static void main( String [] args )
          Scanner scan = new Scanner( System.in );
          TicTacToe ttt1 = new TicTacToe( );
          String garbage;
          int player = 1;
          boolean gameOver = false;
          int position;
          while ( ! gameOver )
               System.out.print( "Please enter a position, player " + player + " > " );
               while( ! scan.hasNextInt( ) )
                    garbage = scan.nextLine( );
                    System.out.print( "Please enter a valid position, player " + player + " > " );
               position = scan.nextInt( );
               if ( ! ttt1.isLegal( position ) )
                    System.out.println( "This position is already used!" );
               else
                    ttt1.makeMove( player, position );
                    if ( ttt1.gameWon( player ) || ttt1.isTie( ) )
                         gameOver = true;
                    else
                         if ( player == 1 )
                              player = 2;
                         else
                              player = 1;
          ttt1.printWinner( player );
}