C++ 读取文件C++；

当我保存

playingBoard

数组时，

save

会正确打印它，但是当我尝试导入用

import

创建的

save

文件时，我会得到奇怪的输出-空格被删除，并替换为没有明显逻辑的

1

s。（示例如下所示）

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");
}

第二次运行时的输出：

1| | | | | | | | |
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1| | | | | | | | |
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第三次运行时的输出：

1|1|1| | | | | | |
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1|1|1| | | | | | |
 |1| | | | | | | |
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---

您的问题是，默认情况下，

操作符>

跳过空白。您需要使用另一种从文件中提取字符的方法，例如

get

成员函数（下面的示例，使用gcc-9.3.0测试）

---

filename

的内容是什么？“该文件以无符号字符值开头，该值表示写入了多少块板。”您将文件中的第一个数字设置为

playingBoard[0][0]

。这正是

save

写入的内容。在首次调用函数之前，该函数不存在。请从文件导入开始。在运行程序之前，文件中有什么？我从程序中删除了

无符号字符

，但忘了从描述中删除它。

1|1|1| | | | | | |
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1|1|1| | | | | | |
 |1| | | | | | | |
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  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;
    }

$ ./a.out 
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