python实现简单井字棋小游戏

#Tic-Tac-Toe 井字棋游戏
#全局常量
X="X"
O="O"
EMPTY=" "
#询问是否继续
def ask_yes_no(question):
response=None;
while response not in("y","n"):
response=input(question).lower()
return response
#输入位置数字
def ask_number(question ,low,high):
response=None
while response not in range(low,high):
response=int(input(question))
return response
#询问谁先走，先走方为X,后走方为O
#函数返回计算机方，玩家的角色代号
def pieces():
go_first=ask_yes_no("玩家你是否先走（y/n):")
if go_first=="y":
print("\n玩家你先走.")
human=X
computer=O
else:
print("\n计算机先走.")
computer=X
human=O
return computer,human
#产生新的棋盘
def new_board():
board=[]
for square in range(9):
board.append(EMPTY)
return board
#显示棋盘
def display_board(board):
board2=board[:]
for i in range(len(board)):
if board[i]==EMPTY:
board2[i]=i
print("\t",board2[0],"|",board2[1],"|",board2[2])
print("\t","----------")
print("\t",board2[3],"|",board2[4],"|",board2[5])
print("\t", "----------")
print("\t",board2[6],"|",board2[7],"|",board2[8],"\n")
#产生可以合法走棋位置序列（也就是还未下过子位置）
def legal_moves(board):
moves=[]
for square in range(9):
if board[square]==EMPTY:
moves.append(square)
return moves
#判断输赢
def winner(board):
# 所有赢得可能情况，例如（0,1,2）就是第一行，（0,4,8,），（2,4,6）就是对角线
WAYS_TO_WIN=((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 in WAYS_TO_WIN:
if board[row[0]]==board[row[1]]==board[row[2]]!=EMPTY:
winner=board[row[0]]
return winner
#棋盘没有空位置
if EMPTY not in board:
return "TIE"
return False
#人走棋
def human_move (board,human):
legal =legal_moves(board)
move =None
while move not in legal:
move=ask_number("你走那个位置？（0-8）：",0,9)
if move not in legal:
print("\n此位置已经落过子了")
#print("Fine...")
return move
#计算机走棋
def computer_move(board,computer ,human):
board=board[:]
#按优劣顺序排序的下棋走子
BEST_MOVES=(4,0,2,6,8,1,3,5,7) #最佳下棋位置顺序表
#如果计算机能赢，就走那个位置
for move in legal_moves(board):
board[move]=computer
if winner(board)==computer:
print("计算机下棋位置...",move)
return move
#取消走棋方案
board[move]=EMPTY
#如果玩家能赢就堵住那个位置
for move in legal_moves(board):
board[move]=human
if winner(board)==human:
print("计算机下棋位置...",move)
return move
#取消走棋方案
board[move]=EMPTY
#如果不是上面情况，也就是这一轮赢不了
#则是从最佳下棋位置表中挑出第一个合法位置
for move in BEST_MOVES:
if move in legal_moves(board):
print("计算机下棋位置....",move)
return move
#转换角色
def next_turn(turn):
if turn ==X:
return O
else:
return X
#主函数
def main():
computer,human=pieces()
turn =X
board=new_board()
display_board(board)
while not winner(board):
if turn ==human:
move=human_move(board,human)
board[move]=human
else:
move=computer_move(board,computer,human)
board[move]=computer
display_board(board)
turn=next_turn(turn) #转换角色
#游戏结束输出输赢或和棋信息
the_winner=winner(board)
if the_winner==computer:
print("计算机赢！\n")
elif the_winner==human:
print("玩家赢！\n")
elif the_winner=="TIE":
print("平局，游戏结束\n")
main()
input("按任意键退出游戏")