(Game: connect four) Programming Exercise 8.20 enables two players to play the connect-four game on the console

 (Game: connect four) Programming Exercise 8.20 enables two players to play the connect-four game on the console. Rewrite a GUI version for the program, as shown in Figure 16.49c. The program enables two players to place red and yellow discs in turn. To place a disk, the player needs to click an available cell. An available cell is unoccupied and its downward neighbor is occupied. The program flashes the four winning cells if a player wins and reports no winners if all cells are occupied with no winners.

(c) The program enables two players to play the connect-four game.