编写一个程序，让两个人在计算机上玩井字游戏

好的，以下是一个简单的 Python 代码实现：

# 定义井字游戏棋盘
board = [' ' for x in range(10)]

# 定义函数：打印棋盘
def print_board(board):
    print('   |   |')
    print(' ' + board[1] + ' | ' + board[2] + ' | ' + board[3])
    print('   |   |')
    print('-----------')
    print('   |   |')
    print(' ' + board[4] + ' | ' + board[5] + ' | ' + board[6])
    print('   |   |')
    print('-----------')
    print('   |   |')
    print(' ' + board[7] + ' | ' + board[8] + ' | ' + board[9])
    print('   |   |')

# 定义函数：判断是否胜利
def is_winner(board, player):
    return (board[1] == board[2] == board[3] == player or
            board[4] == board[5] == board[6] == player or
            board[7] == board[8] == board[9] == player or
            board[1] == board[4] == board[7] == player or
            board[2] == board[5] == board[8] == player or
            board[3] == board[6] == board[9] == player or
            board[1] == board[5] == board[9] == player or
            board[3] == board[5] == board[7] == player)

# 定义函数：判断棋盘是否已满
def is_board_full(board):
    return ' ' not in board[1:]

# 定义函数：玩家下棋
def player_move(board, player):
    while True:
        move = input("请玩家 " + player + " 下棋 (1-9): ")
        try:
            move = int(move)
            if move >= 1 and move <= 9 and board[move] == ' ':
                board[move] = player
                break
            else:
                print("无效的位置，请重新选择。")
        except:
            print("无效的输入，请重新输入。")

# 定义主程序
def main():
    print("欢迎来到井字游戏！")
    print_board(board)
    player1 = 'X'
    player2 = 'O'
    while True:
        player_move(board, player1)
        print_board(board)
        if is_winner(board, player1):
            print("玩家 " + player1 + " 获胜！")
            break
        if is_board_full(board):
            print("平局！")
            break
        player_move(board, player2)
        print_board(board)
        if is_winner(board, player2):
            print("玩家 " + player2 + " 获胜！")
            break
        if is_board_full(board):
            print("平局！")
            break

if __name__ == '__main__':
    main()

玩家可以依次输入要下的位置，如下所示：

欢迎来到井字游戏！
   |   |
   |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
请玩家 X 下棋 (1-9): 1
   |   |
 X |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
请玩家 O 下棋 (1-9): 5
   |   |
 X |   |
   |   |
-----------
   |   |
 O |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
请玩家 X 下棋 (1-9): 2
   |   |
 X | X |
   |   |
-----------
   |   |
 O |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
请玩家 O 下棋 (1-9): 3
   |   |
 X | X | O
   |   |
-----------
   |   |
 O |   |
   |   |
-----------
   |   |
   |   |
   |   |
-----------
请玩家 X 下棋 (1-9): 9
   |   |
 X | X | O
   |   |
-----------
   |   |
 O |   |
   |   |
-----------
   |   |
   |   | X
   |   |
-----------
玩家 X 获胜！