如何从文本文件中读取文件名列表并在C ++中打开它们？ [英] How to read a list of filenames from a text file and open them in C++?

问题描述

我有一个存储在文本文件中的文件列表。我一行一行地读取文件，并将它们存储在一个字符串数组中。文件列表如下所示：

  04_02_1310.csv 
 04_03_1350.csv 
 04_04_0421.csv 
 04_05_0447.csv 
  

等等。让我们调用我的字符串数组
$ b

  filelist [i] 
  

假设我正在尝试打开列表中的第一个文件：

  inputFile 。开（文件列表[0] .c_str（））; //不能打开文件
  

文件无法打开。如果我把文件的名字放在引号中，一切正常：

  inputFile.open（04_02_1310.csv）;如果我打印filelist [i]的内容，那么它工作正常，因为它的作品完美的
  

well：

  cout<< filelist [0]<< ENDL; //在屏幕上输出04_02_1310.csv。 
  

有人可以告诉我上面的方法有什么问题吗？在过去的两天里，这让我疯狂，而且我正在手动输入所有内容（100个以上的文件）。

我是

谢谢!!!

编辑：我是这样简单的任务添加代码的相关部分，如果你想看看它是如何实现的：

  #include< cstdlib> 
 #include< iostream> 
 #include< time.h> 
 #include< string> 
 #include< sstream> 
 #include< fstream> 
 #include< vector> 
 #include< algorithm> 
 #include< iterator> 
 
使用namespace std; 
 
 // I / O文件的声明
 ifstream inputFile; 
 
 //声明其他变量（忘了在我以前的编辑中添加这些变量，对不起）
 int number_of_files; 
字符串行; 
 string * filelist = NULL; 
 
 //打开文件列表并计算文件数量
 inputFile.clear（）; 
 inputFile.open（filelist.txt，ios :: in）; 
 
 //如果文件无法打开，退出并提示错误消息
 if（！inputFile）{
 cerr<< 文件列表无法打开<< ENDL; 
 exit（1）; 
} // end if 
 
 //计算数据文件中的行数和屏幕提示
 number_of_files = 0; 
 
 while（getline（inputFile，line））
 number_of_files ++; 
 
 cout<< 要分析的文件的数量：<< number_of_files<< ENDL; 
 
 filelist = new string [number_of_files]; 
 inputFile.close（）; 
 
 //重新打开文件列表并将文件名保存在字符串数组中
 inputFile.clear（）; 
 inputFile.open（filelist.txt，ios :: in）; 
 
 //如果文件无法打开，退出并提示错误消息
 if（！inputFile）{
 cerr<< 文件列表无法打开<< ENDL; 
 exit（1）; 
} //结束如果
 
 //存储文件名
 i = 0; 
 while（getline（inputFile，line））{
 filelist [i] = line; 
 // cout<< filelist [i]<< ENDL; 
 i = i + 1; 
} 
 
 inputFile.close（）; 
 
 //打开列表中的第一个文件，我删除了这个循环，现在把注意力集中在第一个元素
 
 inputFile.clear（）; 
 inputFile.open（filelist [0] .c_str（），ios :: in）; 
 
 //如果文件无法打开，退出并提示错误消息
 if（！inputFile）{
 cerr<< 数据文件无法打开<< ENDL; 
 exit（1）; 
} // end if 
  

输出结果是：

 无法打开数据文件
  

再次感谢！

解决方案

可能还有'\ n'char（或EOF，'\ 0'），你应该尝试检查字符串是否为干净。

I have a list of files stored in a text file. I read the file line by line and store them in a string array. The file list looks like this:

04_02_1310.csv
04_03_1350.csv
04_04_0421.csv
04_05_0447.csv

and so on. Let's call my string array

filelist[i]

Assuming I am trying the open the first file in the list:

inputFile.open(filelist[0].c_str()); // This cannot open file

the file cannot be opened. If i place the file name in quotation marks, everything works out fine:

inputFile.open("04_02_1310.csv"); // This works perfectly

if i print the contents of filelist[i], then it works fine as well:

cout << filelist[0] << endl; // This outputs 04_02_1310.csv on screen.

Can somebody tell me what is wrong with the approach above? This is driving me crazy for the last 2 days, and I am about the enter everything manually just to get it done (100+ files one after another).

I am also open to any other way to do this simple task.

Thanks!!!

EDIT: I am adding a relevant portion of the code if you would like to see how it is implemented:

#include <cstdlib>
#include <iostream>
#include <time.h>
#include <string>
#include <sstream>
#include <fstream>
#include <vector>
#include <algorithm>
#include <iterator>

using namespace std;

//Declarations for I/O files
ifstream inputFile;

//Declare other variables (forgot to add these in my previous EDIT, sorry)
int number_of_files;
string line;
string *filelist = NULL;

//Open file list and count number of files
inputFile.clear();
inputFile.open("filelist.txt", ios::in);

//exit and prompt error message if file could not be opened
if (!inputFile){
    cerr << "File list could not be opened" << endl;
    exit(1);
}// end if

// count number of lines in the data file and prompt on screen
number_of_files = 0;

while (getline(inputFile, line))        
    number_of_files++;

cout << "Number of files to be analyzed: " << number_of_files << endl;

filelist = new string[number_of_files];
inputFile.close();

//Re-open file list and store filenames in a string array
inputFile.clear();
inputFile.open("filelist.txt", ios::in);

//exit and prompt error message if file could not be opened
if (!inputFile){
    cerr << "File list could not be opened" << endl;
    exit(1);
}// end if

// store filenames
i = 0;
while (getline(inputFile, line)){
    filelist[i] = line;
    //cout << filelist[i] << endl;
    i = i + 1;
}        

inputFile.close();

//open first file in the list, I deleted the loop to focus on the first element for now

inputFile.clear();
inputFile.open(filelist[0].c_str(), ios::in);

//exit and prompt error message if file could not be opened
if (!inputFile){
    cerr << "Data file could not be opened" << endl;
    exit(1);
}// end if

The output is:

Data file could not be opened

Thanks again!

解决方案

It is possible that there still is the '\n' char (or EOF,'\0' ) from your textfile in that string, you should try checking if the strings are "clean".

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