CMIS 340
Homework 1
Due: 7 Apr.

Write a Java application that will play a game of Tic-tac-toe between
two users.

The program will display the 3-by-3 board at the beginning of the game and 
after each move.  Initially the board is empty, none of the nine locations 
have been played.  Then player "O" plays a legal move, that is, a row and 
column coordinate pair that is within the board and that has not already 
been played.  Then player "X" plays.  
Play continues until either one player has won by having three O's or X's 
in a row, column, or diagonal or all nine locations have been played and 
neither player has won (i.e. a tie).
The program detects the winning or tying situation (so after each move it
must check if that move results in a win or tie).

Use public static methods.
Your program must have a method to input a valid move by a player.
It must have a method that displays the board.
It must have a method to check for winning or tying play.

The 3-by-3 2D array that is the board is declared in main and passed
to the methods as an argument.

Use console input and output.  Use our read_int() method.  Try to put
all input and output in methods seperate from code that does logic so
that it will be easier to modify the program to use GUI I/O.

Since this game is between two users (or one user being both players) the 
program is not a player so it doesn't need to know any strategy.

This is basically a 140-level program recast as Java to get us started
with Java.