I am looking for an example of a two-player tic tac toe program that can vary in board size and asks the user how big the board should be (for example, somewhere between 3 and 15; the number must be odd because diagonal paths have to be able to work out since all the original rules of tic tac toe apply).

The program should
- ask for each player to make a move
- update and displays the board after each move
- evaluate the board to see if someone has won or has drawn the game
- exit the program after the game is over

I've never programmed in Pascal before.

Would it be easier to write this sort of program in Pascal with or without an object-oriented design?

Does anyone have examples to show me which would be very similar to what I'm asking for? For example, maybe a varied l

You have some examples with tic-tac-toe here:
http://rosettacode.org/wiki/Tic-tac-toe

Pascal code is not made for this game yet (maybe somewhere else)but take a look at Ada!