// APS101, Winter 2009: Lecture 30 (Mar. 24)
//
// Review: last time we wrote a GUI for our Tic-Tac-Toe game.

TicTacToe t = new TicTacToe();
TTTWindow w = new TTTWindow(t);
t.setMark('X', 1,1)
w.update(1,1)

// in order to play the game, you would need to keep doing this.
// so, instead of doing this manually, we write a "main" method:
            
            public static void main(String[] args) 

// This is the starting point of the program.
// After compiling, to run the program you can type in:

            java ProgramName

// where ProgramName is a .class file containing the main method.

// also, you can pass arguments to the main method:

            java ProgramName arg1 arg2 ...

// then, in the main method, args[0] is arg1, args[1] is arg2 and so on.

// (see TTTDriver.java that we wrote in class)

java TTTDriver // this is all you need to do to run the game!

// as an exercise, make the driver more robust (error-resistant):

   1. if the user enters non-numbers or out of range row/column, ask again
      until row and column are valid.

   2. if the row/column is valid but already occupied, tell the user to choose an 
      empty cell, and keep asking for a valid cell.

      The best way to do this is to change the setMark() method to return true/false
      (false if the cell is not BLANK), so in the driver if you setMark
      and it is false you know the cell was not BLANK.

   3. re-write the GUI so that the grid is composed of JButtons, rather than JLabels.
      Make these buttons clickable, so that the user does not need to enter a row and
      a column to make a mark on the grid.