读取文件时的奇怪错误C++

提问者：小点点

读取文件时的奇怪错误C++

当我保存playingboard数组时，save会正确地打印它，但是当我尝试导入用import创建的save文件时，我得到了奇怪的输出--空格被删除，并被没有明显逻辑的1s替换。（示例如下）

最小可复制示例:

#include <iostream>
#include <fstream>

class Board
{
public:
  char playingBoard[9][9];
  
  Board()
  {
    for (unsigned char i = 0; i < 9; ++i)
      for (unsigned char j = 0; j < 9; ++j)
        playingBoard[i][j] = ' ';
  }

  bool import(std::string filename)
  {
    std::ifstream ifs {filename};
    if (!ifs.is_open())
      return false;

    for (unsigned char i = 0; i < 9; ++i) {
      for (unsigned char j = 0; j < 9; ++j) {
        ifs >> playingBoard[i][j];
        std::cout << playingBoard[i][j] << "|";
      }
      std::cout << std::endl;
    }
  
    ifs.close();
    return true;
  }

  bool save(std::string filename) const
  {
    std::ofstream ofs {filename, std::ios::app};
    if (!ofs.is_open())
      return false;
  
    for (unsigned char i = 0; i < 9; ++i) {
      for (unsigned char j = 0; j < 9; ++j) {
        ofs << playingBoard[i][j];
        std::cout << playingBoard[i][j] << "|";
      }
      std::cout << std::endl;
    }
  
    ofs.close();
    return true;
  }
};

int main()
{
  Board board;
  board.import("filename");
  
  std::cout << std::endl;
  board.playingBoard[1][1] = '1';
  board.save("filename");
}

第一次运行时的输出（文件以前不存在，因此只有一个输出）:

 | | | | | | | | |
 |1| | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

第二次运行时的输出:

1| | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

1| | | | | | | | |
 |1| | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

第三次运行时的输出:

1|1|1| | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

1|1|1| | | | | | |
 |1| | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

共1个答案

匿名用户

您的问题是，默认情况下，使用operator>>会跳过空格。您需要使用另一种方法从文件中提取字符，例如get成员函数（下面的示例，用GCC-9.3.0测试）。

  bool import(std::string filename)
  {
    std::ifstream ifs {filename};
    if (!ifs.is_open())
      return false;

    for (unsigned char i = 0; i < 9; ++i) {
      for (unsigned char j = 0; j < 9; ++j) {
        playingBoard[i][j] = ifs.get();
        std::cout << playingBoard[i][j] << "|";
      }
      std::cout << std::endl;
    }

输出:

$ ./a.out 
 | | | | | | | | |
 |1| | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

 | | | | | | | | |
 |1| | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |
 | | | | | | | | |

读取文件时的奇怪错误C++

共1个答案

相关问题