输入字母字符时，Tic-Tac-Toe用户输入无休止地循环

# 初始化棋盘
board = [[' ', ' ', ' '], [' ', ' ', ' '], [' ', ' ', ' ']]
current_player = 'X'

# 游戏循环
while True:
    # 打印当前棋盘状态
    print_board(board)

    # 提示当前玩家输入位置
    position = input("Player " + current_player + ", enter your move (row[1-3] column[1-3]): ")

    # 输入验证
    if not is_valid_input(position):
        print("Invalid input. Please enter a letter character.")
        continue

    # 将输入转换为棋盘位置
    row, col = convert_input(position)

    # 检查位置是否已经被占据
    if is_occupied(board, row, col):
        print("Position already occupied. Please choose another position.")
        continue

    # 更新棋盘状态
    board[row][col] = current_player

    # 检查是否达到胜利条件
    if is_winner(board, current_player):
        print("Player " + current_player + " wins!")
        break

    # 检查是否达到平局
    if is_draw(board):
        print("It's a draw!")
        break

    # 切换玩家
    current_player = 'O' if current_player == 'X' else 'X'