You have to write is_full and all the other methods that I have not as
yet written in order to get the play2 unit to work completely. Play2
uses BoardADT. Here is a run-down on the methods not written in class.
1. Is_draw is true when all the squares on the top row are occuppied.
(This is needed to test whether a draw has occurred.)
2. Is_full is true when the square in the top row of the column is occupied.
(This tests whether you can place a checker in a column.)
3. Get_value returns as a var parameter "Val". This is assigned
value[ square.column, square.row ] in the procedure.
(This is needed to place a checker in other rows than the first row.
If it is not there, every checker will be placed in the botton row.)
4. Is_win checks for winning combinations.