需要从输入文件中跳过换行符 (\n)

发布于 2024-08-26 23:33:04 字数 625 浏览 11 评论 0原文

我正在将文件读入数组。它正在读取每个字符，出现的问题是它还读取文本文件中的换行符。

这是一个数独板，这是我读取字符的代码：

bool loadBoard(Square board[BOARD_SIZE][BOARD_SIZE])
{
  ifstream ins;

  if(openFile(ins)){

    char c;

    while(!ins.eof()){
      for (int index1 = 0; index1 < BOARD_SIZE; index1++)
        for (int index2 = 0; index2 < BOARD_SIZE; index2++){ 
          c=ins.get();

          if(isdigit(c)){
            board[index1][index2].number=(int)(c-'0');
            board[index1][index2].permanent=true;
          }
        }
    }

    return true;
  }

  return false;
}

就像我说的，它读取文件，显示在屏幕上，只是当遇到 \n 时顺序不正确

原文

I am reading in a file into an array. It is reading each char, the problem arises in that it also reads a newline in the text file.

This is a sudoku board, here is my code for reading in the char:

bool loadBoard(Square board[BOARD_SIZE][BOARD_SIZE])
{
  ifstream ins;

  if(openFile(ins)){

    char c;

    while(!ins.eof()){
      for (int index1 = 0; index1 < BOARD_SIZE; index1++)
        for (int index2 = 0; index2 < BOARD_SIZE; index2++){ 
          c=ins.get();

          if(isdigit(c)){
            board[index1][index2].number=(int)(c-'0');
            board[index1][index2].permanent=true;
          }
        }
    }

    return true;
  }

  return false;
}

like i said, it reads the file, displays on screen, just not in correct order when it encounters the \n

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可是我不能没有你 2024-09-02 23:33:04

您可以将 ins.get() 放入 do while 循环中：

do { 
    c=ins.get();
} while(c=='\n');

You can put you ins.get() in a do while loop:

do { 
    c=ins.get();
} while(c=='\n');

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赠我空喜 2024-09-02 23:33:04

那么在您的文件格式中，您可以简单地不保存换行符，或者您可以添加一个 ins.get() for 循环。

您还可以将 c=ins.get() 包装在类似 getNextChar() 的函数中，该函数将跳过任何换行符。

我想你想要这样的东西：

 for (int index1 = 0; index1 < BOARD_SIZE; index1++)
 {
  for (int index2 = 0; index2 < BOARD_SIZE; index2++){

   //I will leave the implementation of getNextDigit() to you
   //You would return 0 from that function if you have an end of file
   //You would skip over any whitespace and non digit char.
   c=getNextDigit();
   if(c == 0)
     return false;

   board[index1][index2].number=(int)(c-'0');
   board[index1][index2].permanent=true;
  }
 }
 return true;

Well in your file format you can simply not save newlines, or you can add a ins.get() the for loop.

You could also wrap your c=ins.get() in a function something like getNextChar() which will skip over any newlines.

I think you want something like this:

 for (int index1 = 0; index1 < BOARD_SIZE; index1++)
 {
  for (int index2 = 0; index2 < BOARD_SIZE; index2++){

   //I will leave the implementation of getNextDigit() to you
   //You would return 0 from that function if you have an end of file
   //You would skip over any whitespace and non digit char.
   c=getNextDigit();
   if(c == 0)
     return false;

   board[index1][index2].number=(int)(c-'0');
   board[index1][index2].permanent=true;
  }
 }
 return true;

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飞烟轻若梦 2024-09-02 23:33:04

您有一些不错的选择。要么不要将换行符保存在文件中，在循环中显式丢弃它们，要么使用 < 中的 code>std::getline()。

例如，使用 getline()：

#include <string>
#include <algorithm>
#include <functional>
#include <cctype>

using namespace std;

// ...

string line;
for (int index1 = 0; index1 < BOARD_SIZE; index1++) {
    getline(is, line); // where is is your input stream, e.g. a file
    if( line.length() != BOARD_SIZE )
        throw BabyTearsForMommy();
    typedef string::iterator striter;
    striter badpos = find_if(line.begin(), line.end(),
                             not1(ptr_fun<int,int>(isdigit)));
    if( badpos == line.end() )
        copy(board[index1], board[index1]+BOARD_SIZE, line.begin());
}

You have a few good options. Either don't save the newline in the file, explicitly discard them in your loop, or use std::getline() in <string>.

For example, using getline():

#include <string>
#include <algorithm>
#include <functional>
#include <cctype>

using namespace std;

// ...

string line;
for (int index1 = 0; index1 < BOARD_SIZE; index1++) {
    getline(is, line); // where is is your input stream, e.g. a file
    if( line.length() != BOARD_SIZE )
        throw BabyTearsForMommy();
    typedef string::iterator striter;
    striter badpos = find_if(line.begin(), line.end(),
                             not1(ptr_fun<int,int>(isdigit)));
    if( badpos == line.end() )
        copy(board[index1], board[index1]+BOARD_SIZE, line.begin());
}

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