Changing the game's internal representation

exercise No. 146

Q:

This exercise aims at changing the subsequent items with respect to the previous Tic-tac-toe solution:

End user perspective
  1. End users are used to count from 1 to 9 rather than from 0 to 8. Consequently we should supply a different hint regarding the fields' numbering scheme:

    012
    345
    678
    123
    456
    789
  2. The two players should have a choice about who is to start a game:

    Numbering scheme:
    
    1|2|3
    -+-+-
    4|5|6
    -+-+-
    7|8|9
    
    
    Who is going to start? 0 = June, other = Bill
    0
    
    
    June, please enter next field's number:
  3. The numbering hints should appear right to the current tic-tac-toe board rather than on top of it. Furthermore only the remaining free fields shall be on offer. In the next example this restriction excludes position 4:

    Player June(O)
    vs. Bill(X)          Free fields
    
     | |                   1|2|3
    -+-+-                  -+-+-
    O| |                    |5|6
    -+-+-                  -+-+-
     | |                   7|8|9
    
    Bill, please enter next field's number:

A: