fix the comments for check_for_winner

[helpingstar]

Description

To determine the winner, tic tac toe uses check_for_winner(), defined in tictactoe/board.py. That function describes its returns as -1, 0, 1 in the comments as follows. However, the check_for_winner() function returns -1, 1, 2.

PettingZoo/pettingzoo/classic/tictactoe/board.py

Lines 51 to 65 in f7a9ef1

	# returns:
	# -1 for no winner
	# 0 -- agent 0 wins
	# 1 -- agent 1 wins
	def check_for_winner(self):
	winner = -1
	for combination in self.winning_combinations:
	states = []
	for index in combination:
	states.append(self.squares[index])
	if all(x == 1 for x in states):
	winner = 1
	if all(x == 2 for x in states):
	winner = 2
	return winner

Other functions that use the check_for_winner() function also run the function thinking that the integers it returns are -1, 1, and 2. This leads us to believe that we should change the function's comment.

PettingZoo/pettingzoo/classic/tictactoe/board.py

Lines 67 to 76 in f7a9ef1

	def check_game_over(self):
	winner = self.check_for_winner()
	if winner == -1 and all(square in [1, 2] for square in self.squares):
	# tie
	return True
	elif winner in [1, 2]:
	return True
	else:
	return False

PettingZoo/pettingzoo/classic/tictactoe/tictactoe.py

Lines 212 to 225 in f7a9ef1

	if self.board.check_game_over():
	winner = self.board.check_for_winner()
	if winner == -1:
	# tie
	pass
	elif winner == 1:
	# agent 0 won
	self.rewards[self.agents[0]] += 1
	self.rewards[self.agents[1]] -= 1
	else:
	# agent 1 won
	self.rewards[self.agents[1]] += 1
	self.rewards[self.agents[0]] -= 1

The observe function also shows a correspondence of 1 -> agent0, 2 -> agent1.

PettingZoo/pettingzoo/classic/tictactoe/board.py

Lines 10 to 12 in f7a9ef1

	# empty -- 0
	# player 0 -- 1
	# player 1 -- 2

Type of change

• fix comment

Screenshots

before

after

Checklist:

• I have run the pre-commit checks with pre-commit run --all-files (see CONTRIBUTING.md instructions to set it up)
• I have run pytest -v and no errors are present.
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I solved any possible warnings that pytest -v has generated that are related to my code to the best of my knowledge.
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[elliottower]

Thanks for catching this, looks good. The original code there isn't the cleanest by any means, could probably be made a bit less confusing, but it does what it's supposed to and isn't worth changing around IMO, so best to just make sure the comments reflect the current behavior