In the starter code, you are given an interface representing a game of Tic Tac Toe; your task is to implement the TicTacToe interface.
You will need to define an enum Player, representing the players (X and O), with a toString() method that returns "X" and "O" accordingly. You will need to implement the public class named TicTacToeModel, with a single public constructor that takes no arguments. The class definition, with a toString() implementation to help with debugging, are provided to you in the starter code. You will fill in the fields and remaining method definitions as appropriate. You may also define other classes at your option as needed.
The game grid cells are numbered by row and column starting from 0. For example, the upper left position is row 0, column 0 (or [0][0] in the 2D array returned by getBoard()), the upper middle position is row 0, column 1 ([0][1]), the lower right is [2][2].