Question

我需要读取一个文件，其中包含其他文件的路径，类型以及有关它们的其他数据。该文件看起来像，

LIST OF SUB DIRECTORIES:
Advanced System Optimizer 3
ashar wedding and home pics
components
Documents and Settings
khurram bhai
media
new songs
Office10
Osama
Program Files
RECYCLER
res
Stationery
System Volume Information
Templates
WINDOWS



LIST OF FILES:
.docx  74421
b.com  135168
ChromeSetup.exe  567648
Full & final.CPP  25884
hgfhfh.jpg  8837
hiberfil.sys  267964416
myfile.txt.txt  0
pagefile.sys  402653184
Shortcut to 3? Floppy (A).lnk  129
Thumbs.db  9216
vcsetup.exe  2728440
wlsetup-web.exe  1247056

我只需要提取文件的路径名并将它们保存在一个数组中，但我坚持使用它。这是我的代码，

// read a file into memory
#include <iostream>
#include <fstream>
using namespace std;

int main () {
  int length;
  char str[600];

  ifstream is;
  is.open ("test.txt", ios::binary );

  // get length of file:
  is.seekg (0, ios::end);
  length = is.tellg();
  is.seekg (0, ios::beg);


  // read data as a block:
  is.read (str,length);
  //**find the path of txt files in the file and save it in an array...Stuck here**
  is.close();
  return 0;
}

我很困惑接下来要做什么。即使我使用strstr（）找到.txt，无论什么时候我都会得到它的整个路径？

Answer 1

也许你应该看看boost filesystem library。

它提供了您需要的东西。

这应该是一个如何运作的例子。它应该编译，虽然我没有尝试。

boost::filesystem::path p("test.txt");
boost::filesystem::path absolutePath = boost::filesystem::system_complete(p);
boost::filesystem::path workDir = absolutePath.parent_path();

std::vector<std::string> file;
std::string line;
std::ifstream infile ("test.txt", std::ios_base::in);
while (getline(infile, line, '\n'))
{
    file.push_back (line.substr(0, line.find_first_of(" ")));
}

std::vector<std::wstring> fullFileNames;
for(std::vector<std::string>::const_iterator iter = file.begin(); iter != file.end(); ++iter)
{
    boost::filesystem::path newpath= workDir / boost::filesystem::path(*iter);
    if(!boost::filesystem::is_directory(newpath) && boost::filesystem::exists(newpath))
    {
        fullFileNames.push_back(newpath.native().c_str());
    }
}

当然，它缺乏各种错误检查。

Answer 2

如果您只需要提取路径，文件始终如下所示，您可以逐行读取文件并使用string::find查找第一个出现的空格并在每个条目中创建一个子字符串。

size_t index = str.find(" ");
if(index != string::npos) // sanity checing
{
   string path = str.substr(0, index);
   //do whatever you want to do with the file path
}

Answer 3

您要实现的目标实际上是演示如何在cplusplus.com上使用string::find_last_of的示例代码：

void SplitFilename (const string& str)
{
  size_t found;
  cout << "Splitting: " << str << endl;
  found=str.find_last_of("/\\");
  cout << " folder: " << str.substr(0,found) << endl;
  cout << " file: " << str.substr(found+1) << endl;
}

Answer 4

如果你想获得当前目录中给定文件的整个路径，下面的代码为你做了，当然使用boost：

#include <iostream>

#define BOOST_FILESYSTEM_VERSION 3
#include <boost/filesystem.hpp>
namespace fs = boost::filesystem;

int main()
{
  fs::path my_path("test.txt");
  if(fs::is_regular_file(my_path)) // Sanity check: the file exists and is a file (not a directory)
  {
    fs::path wholePath = fs::absolute(my_path);
    std::cout << wholePath.string() << std::endl;
  }

  return 0;
}

如何从文件中提取出路径？

4 个答案: