Tic-tac-toe: Difference between revisions

FOR I = 0 TO 7

IF Board(WinPos(I, 0)) = Piece AND Board(WinPos(I, 1)) = Piece AND Board(WinPos(I, 2)) = Piece THEN Win = -1: EXIT FUNCTION

NEXT I

Win = 0

END FUNCTION

</syntaxhighlight>

==={{header|RapidQ}}===

{{trans|QuickBASIC}}

<syntaxhighlight lang="basic">

' Tic-tac-toe

' Console application

DECLARE FUNCTION Win (Piece AS STRING) AS INTEGER

DECLARE FUNCTION SpacesFilled () AS INTEGER

DECLARE SUB ClearBoard ()

DECLARE SUB DisplayNumberedBoard ()

DECLARE SUB DisplayPiecedBoard ()

DECLARE FUNCTION Evaluate (Me AS STRING, Him AS STRING) AS INTEGER

DIM Board(9) AS STRING * 1, BestMove AS INTEGER

DIM WinPos(8, 2) AS INTEGER

DIM MyPiece AS STRING, HisPiece AS STRING

FOR I = 0 TO 7

FOR J = 0 TO 2

READ WinPos(I, J)

NEXT J

NEXT I

' Winning positions

DATA 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 3, 6, 1, 4, 7, 2, 5, 8, 0, 4, 8, 2, 4, 6

MyWinsCnt = 0: HisWinsCnt = 0: DrawsCnt = 0

CompFirst = -1 ' It be reversed, so human goes first

CLS

PRINT

PRINT " TIC-TAC-TOE"

PRINT

PRINT "In this version, X always goes first."

PRINT "The board is numbered:"

DO

CompFirst = NOT CompFirst ' reverse who goes first

MovesCnt = 0

PRINT

DisplayNumberedBoard

PRINT

PRINT IIF(CompFirst, "I go first.", "You go first.")

ClearBoard

IF CompFirst THEN MyPiece = "X": HisPiece = "O" ELSE MyPiece = "O": HisPiece = "X"

' -1: human; 1: computer; 0: nobody

Mover = IIF(CompFirst, 1, -1)

WHILE Mover <> 0

SELECT CASE Mover

CASE 1

IF MovesCnt = 0 THEN

BestMove = INT(RND * 9)

ELSEIF MovesCnt = 1 THEN

BestMove = IIF(Board(4) <> " ", INT(RND * 2) * 6 + INT(RND * 2) * 2, 4)

ELSE

T = Evaluate(MyPiece, HisPiece)

END IF

Board(BestMove) = MyPiece

INC(MovesCnt)

PRINT

CALL DisplayPiecedBoard

PRINT

IF Win(MyPiece) THEN

INC(MyWinsCnt)

PRINT "I win!"

Mover = 0

ELSEIF SpacesFilled THEN

INC(DrawsCnt)

PRINT "It's a draw. Thank you."

Mover = 0

ELSE

Mover = -1

END IF

CASE -1

DO

INPUT "Where do you move? ",I

IF I < 1 OR I > 9 THEN

PRINT "Illegal! ";

ELSEIF Board(I - 1) <> " " THEN

PRINT "Place already occupied. ";

ELSE

EXIT DO

END IF

LOOP

Board(I - 1) = HisPiece

INC(MovesCnt)

PRINT

CALL DisplayPiecedBoard

PRINT

IF Win(HisPiece) THEN

INC(HisWinsCnt)

PRINT "You beat me! Good game."

Mover = 0

ELSEIF SpacesFilled THEN

INC(DrawsCnt)

PRINT "It's a draw. Thank you."

Mover = 0

ELSE

Mover = 1

END IF

END SELECT

WEND

PRINT

INPUT "Another game (y/n)? ", Answ$

LOOP UNTIL UCASE$(Answ$) <> "Y"

PRINT

PRINT "Final score:"

PRINT "You won "; HisWinsCnt; " game"; IIF(HisWinsCnt <> 1, "s.", ".")

PRINT "I won "; MyWinsCnt; " game"; IIF(MyWinsCnt <> 1, "s.", ".")

PRINT "We tied "; DrawsCnt; " game"; IIF(DrawsCnt <> 1, "s.", ".")

PRINT "See you later!"

END

SUB ClearBoard

FOR I = 0 TO 8: Board(I) = " ": NEXT I

END SUB

SUB DisplayNumberedBoard

FOR I = 0 TO 8 STEP 3

PRINT " "; I + 1; " | "; I + 2; " | "; I + 3

IF I <> 6 THEN PRINT "---+---+---"

NEXT I

END SUB

SUB DisplayPiecedBoard

FOR I = 0 TO 8 STEP 3

PRINT " "; Board(I); " | "; Board(I + 1); " | "; Board(I + 2)

IF I <> 6 THEN PRINT "---+---+---"

NEXT I

END SUB

FUNCTION Evaluate (Me AS STRING, Him AS STRING)

' Recursive algorithm

DIM I AS INTEGER, SafeMove AS INTEGER, V AS INTEGER, LoseFlag AS INTEGER

IF Win(Me) THEN Evaluate = 1: EXIT FUNCTION

IF Win(Him) THEN Evaluate = -1: EXIT FUNCTION

IF SpacesFilled THEN Evaluate = 0: EXIT FUNCTION

LoseFlag = 1

I = 0

WHILE I <= 8

IF Board(I) = " " THEN

Board(I) = Me ' Try the move.

V = Evaluate(Him, Me)

Board(I) = " " ' Restore the empty space.

IF V = -1 THEN BestMove = I: Evaluate = 1: EXIT FUNCTION

IF V = 0 THEN LoseFlag = 0: SafeMove = I

END IF

INC(I)

WEND

BestMove = SafeMove

Evaluate = -LoseFlag

END FUNCTION

FUNCTION SpacesFilled

FOR I = 0 TO 8

IF Board(I) = " " THEN SpacesFilled = 0: EXIT FUNCTION

NEXT I

SpacesFilled = -1

END FUNCTION

FUNCTION Win (Piece AS STRING)