Table of Contents

Tic Tac Toe Game

Functions

Function Parameters Return Value Purpose
isntr() None None display instructions
firstPlayer() None goesFirst selects which piece will move first
choosePiece() None playerPiece allows the player to choose a playing piece
createBoard() None gameBoard creates a game board
displayBoard() gameBoard None prints a game board to the screen
legalMoves() gameBoard legalMoves finds/returns a list of legal moves
winner() gameBoard winner or “TIE” checks for and returns a winner
playerMove() gameBoard, playerPiece playerMove allows player to move and returns space of that move
cpuMove() gameBoard, cpuPiece cpuMove allows cpu to move and returns space of that piece
nextTurn() currTurn nextPiece selects next piece to move and returns that piece
congrats() winner None congratulations the game's winner

Pseudocode

instr()

print "*insert game instructions here*"

firstPlayer()

select a number between 0 & 1 at random

if the number is 0 then goesFirst is O
otherwise goesFirst is X

return goesFirst

choosePiece()

print "Play as X or O: "
get playerPiece

return playerPiece

createBoard()

board = []

for i from 0 to 9
 append " " to board

return board

displayBoard(gameBoard)

for i from 0 to 9
 print gameBoard[i]

legalMoves(gameBoard)

legalMoves = []
for i from 0 to 9
  if gameBoard[i] == EMPTY
    append gameBoard[i] to legalMoves
return legalMoves

winner(gameBoard)

WINS = ((0, 1, 2), (3, 4, 5), (6, 7, 8),
        (0, 3, 6), (1, 4, 7), (2, 5, 8),
        (0, 4, 8), (2, 4, 6))

for row from 0 to 8
  if gameBoard[row[0]] == gameBoard[row[1]] == gameBoard[row[2]] != " ":
    winner = gameBoard[row[0]]
    return winner
  else if no empty spaces
    return "Tie"
return None

playerMove(gameBoard, playerPiece)

print "Enter a move (0-8): "
get move

while move is not from 0 to 8 and board[move] is not in legalMoves
  print "Enter a move (0-8): "
  get move

return move

cpuMove(gameBoard, cpuPiece)

boardCopy = gameBoard[:]
BEST_MOVES = (4, 0, 2, 6, 8, 1, 3, 5, 7)

print "Taking square"

//If computer can win
for move in legalMoves(boardCopy)
  boardCopy[move] = computer
  if winner(boardCopy) is computer
    print move
    return move
  boardCopy[move] = " "

//if the player can win
for move in legalMoves(boardCopy)
  boardCopy[move] = computer
  if winner(boardCopy) is player
    print move
    return move
  boardCopy[move] = " "

//otherwise no winner pick best square
for move in BEST_MOVES
  if move in legalMoves(boardCopy)
    print move
    return move

nextTurn(currTurn)

if currTurn is "X"
  nextTurn = "O"
else
  nextTurn = "X"
return nextTurn

congrats(gameBoard)

if winner(gameBoard) is not "Tie"
  print "Congratulations", winner(gameBoard), "you win!"
else
  "It's a tie!"