We continued with the tic-tac-toe project today. For those students that had not got their
3x3 grid and rollovers to work completely in Tuesday's class, Jonathan did a short review
session. Next, we tackled the problem of marking squares.
To make it easy to program the process of marking a square, Jonathan introduced the concept
of functions. He asked what had to happen each time a square was clicked, and the students
told him that the screen had to show the proper mark, and the current player had to be
alternated. The students then wrote these two steps into a "function" that was separate from
(but called by) all the individual images on the board.
Jonathan also asked, if this function was indeed separate so it "could not see the board,"
what was the one thing it needed to know each time a play was made. The students told him
the function needed to know which spot was clicked on, so we wrote that into the code. By
the end of the class, our code had the rollovers and the ability to mark spots with
alternating x's and o's.