[Tutor] Reversi Game Logic
Mark Lawrence
breamoreboy at yahoo.co.uk
Fri Mar 20 04:12:30 CET 2015
On 20/03/2015 00:50, niyanaxx95 at gmail.com wrote:
From just a quick glance seeing it's 3 in the morning here.
> I am having trouble with a function in my reversi logic code. The function is the isLegalMove I am asked to "Return a Boolean indicating if the current player can place their chip in the square at position (row, col). Both row and col must be valid indices." So I came up with my code below, however a move I make in the game says Error: not a legal move. Please help!
>
> Code:
>
> from ezarrays import Array2D
>
> # Values representing the color of the chips on the board.
> EMPTY = 0
> BLACK = 1
> WHITE = 2
>
>
> class ReversiGameLogic :
>
> # Creates an instance of Reversi game logic with the board correctly
> # initialized and the current player set to black.
> def __init__(self) :
> # Use a 2-D array to represent the board.
> self._gameBoard = Array2D(8, 8)
> self._gameBoard.clear(EMPTY)
>
> # Set the initial configuration of the board.
> self._gameBoard[4,3] = BLACK
> self._gameBoard[3,4] = BLACK
> self._gameBoard[3,3] = WHITE
> self._gameBoard[4,4] = WHITE
>
> # Maintain the number of the current player.
> self._currentPlayer = BLACK
>
> # Keep track of the number of each players chips.
> self._numBlackChips = 2
> self._numWhiteChips = 2
>
> # A flag that is set when the game is over. That is, when there are
> # no empty squares on the board or neither player can make a move.
> self._gameOver = False
>
> # Returns a boolean indicating whether the game is over.
> def isOver(self) :
> isOver = 0
> for i in range(8) :
> for j in range(8) :
> if self._gameBoard[i, j] != 0 :
> isOver + 1
The above line does nothing.
> if isOver == 64 :
> self._gameOver = True
> return True
> else:
> return False
>
> # Returns the player number of the current player.
> def whoseTurn(self) :
> if self._currentPlayer == 1:
> return 1
> else:
> self._curentPlayer == 2
The above line has two errors.
> return 2
>
> # Returns the number of chips on the board for the given player.
> def numChips(self, player) :
> chipCounter = 0
> if player == 1 :
> for i in range(8) :
> for j in range(8) :
> if self._gameBoard[i, j] == BLACK :
> chipCounter = chipCounter + 1
> else :
> for i in range(8) :
> for j in range(8) :
> if self._gameBoard[i, j] == WHITE :
> chipCounter = chipCounter + 1
> return chipCounter
>
You can greatly simplify the above function - I'll let you think about it :)
> # Returns the number of open squares on the board.
> def numOpenSquares(self) :
> numOpenSquares = 0
> for i in range(8) :
> for j in range(8) :
> if self._gameBoard[i, j] == EMPTY :
> numOpenSquares = numOpenSquares + 1
> return numOpenSquares
>
> # Returns the player number of the winner or 0 if it's a draw.
> def getWinner( self ):
> player1 = 0
> player2 = 0
> if self._gameOver is True :
> for i in range(8) :
> for j in range(8) :
> if self._gameBoard[i, j] == BLACK :
> player1 = player1 + 1
> else :
> player2 = player2 + 1
> if player1 > player2 :
> return 1
> if player2 > player1 :
> return 2
> else:
> return 0
>
> # Returns the
> def isLegalMove( self, row, col):
> if row < 8 and col < 8:
In Python the above line can be written.
if row < 8 > col:
> if self._gameBoard[row,col] != EMPTY:
> return True
> else:
> return False
>
> # Returns the player number whose chip occupies the given square.
> def occupiedBy(self, row, col):
> if self._gameBoard[row, col] == BLACK :
> return 1
> if self._gameBoard[row, col] == WHITE :
> return 2
> else:
> return 0
>
> # Performs an actual move in the game. That is the current player places
> # one of his chips in the square at position (row, col).
> def makeMove( row, col ):
> if isALineOfAttack(row, col, 1, 1) is True :
> if self._currentPlayer == 1 :
> self._gameBoard[row, col] = BLACK
> else :
> self._gameBoard[row, col] = WHITE
>
> # Helper method that returns a Boolean indicating if there is a line of
> # attack from cell (row, col) in the direction offset given by rowInc
> # and colInc. The direction offsets should be, 0, 1, or -1.
> def _isALineOfAttack(self, row, col, rowInc, colInc) :
> row += rowInc
> col += colInc
> # The next cell in the line must contain the opponents chip.
> if self.occupiedBy(row, col) == self._currentPlayer :
> return False
>
> # Traverse along the line and determine if it's a line of attack.
> while row >= 0 and col >= 0 and row < 8 and col < 8 :
Again Python comparisons don't need to be written like this.
> if self.occupiedBy(row, col) == self._currentPlayer :
> return True
> elif self.occupiedBy(row, col) == EMPTY :
> return False
> else :
> row += rowInc
> col += colInc
> if row < 0 or row > 7 or col < 0 or col > 7 :
> return False
> return False
--
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.
Mark Lawrence
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