How do I get a list of files in a directory in C++?

Question

How do you get a list of files within a directory so each can be processed?

score 61 · Answer 1 · edited Nov 18 '13 at 11:19

Here's what I use:

/* Returns a list of files in a directory (except the ones that begin with a dot) */

void GetFilesInDirectory(std::vector<string> &out, const string &directory)
{
#ifdef WINDOWS
    HANDLE dir;
    WIN32_FIND_DATA file_data;

    if ((dir = FindFirstFile((directory + "/*").c_str(), &file_data)) == INVALID_HANDLE_VALUE)
        return; /* No files found */

    do {
        const string file_name = file_data.cFileName;
        const string full_file_name = directory + "/" + file_name;
        const bool is_directory = (file_data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0;

        if (file_name[0] == '.')
            continue;

        if (is_directory)
            continue;

        out.push_back(full_file_name);
    } while (FindNextFile(dir, &file_data));

    FindClose(dir);
#else
    DIR *dir;
    class dirent *ent;
    class stat st;

    dir = opendir(directory);
    while ((ent = readdir(dir)) != NULL) {
        const string file_name = ent->d_name;
        const string full_file_name = directory + "/" + file_name;

        if (file_name[0] == '.')
            continue;

        if (stat(full_file_name.c_str(), &st) == -1)
            continue;

        const bool is_directory = (st.st_mode & S_IFDIR) != 0;

        if (is_directory)
            continue;

        out.push_back(full_file_name);
    }
    closedir(dir);
#endif
} // GetFilesInDirectory

The Windows code doesn't quite work when compiled with Unicode enabled. I got around this by explicitly calling the ASCII functions, which have an 'A' appended. Specifically, use WIN32_FIND_DATAA, FindFirstFileA, and FindNextFileA and everything works. Obviously this is a hack, but I live in an English speaking country so it works for me. :0 Thanks for the example code! — Joe, Dec 18 '15 at 19:29
@tuple_cat ``, `` and for sure some kind of file that includes `std::string`. Using `std::string`, you have to put `std::` in front of the `string` type declaration and use `opendir(directory.c_str())`. — Cedric, Mar 22 '17 at 02:45

score 36 · Accepted Answer · edited Mar 22 '19 at 14:54

36

But boost::filesystem can do that: http://www.boost.org/doc/libs/1_37_0/libs/filesystem/example/simple_ls.cpp

edited Mar 22 '19 at 14:54

Community

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answered Nov 20 '08 at 19:24

Johannes Schaub - litb

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score 29 · Answer 3 · edited Oct 05 '17 at 17:58

29

Here's an example in C on Linux. That's if, you're on Linux and don't mind doing this small bit in ANSI C.

#include <dirent.h>

DIR *dpdf;
struct dirent *epdf;

dpdf = opendir("./");
if (dpdf != NULL){
   while (epdf = readdir(dpdf)){
      printf("Filename: %s",epdf->d_name);
      // std::cout << epdf->d_name << std::endl;
   }
}
closedir(dpdf);

edited Oct 05 '17 at 17:58

Antonio

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answered Nov 20 '08 at 21:30

Chris Kloberdanz

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don't forget to `closedir(dpdf)` afterwards – jsj Aug 07 '15 at 02:25
how can i get a file (FILE type) in this case? epdf is a "dirent *" – Alex Goft Apr 05 '16 at 11:05
Can't use dirent if you are making a lib. – Katianie May 25 '16 at 22:36
@Katianie Why not? – byxor Feb 22 '18 at 23:44
1

What do `dpdf` and `epdf` stand for? – byxor Mar 07 '18 at 09:53
1

I was working with PDFs at the time. Those names could be anything you like. – Chris Kloberdanz Mar 08 '18 at 20:55

score 6 · Answer 4 · answered Sep 07 '17 at 22:00

C++11/Linux version:

#include <dirent.h>

if (auto dir = opendir("some_dir/")) {
    while (auto f = readdir(dir)) {
        if (!f->d_name || f->d_name[0] == '.')
            continue; // Skip everything that starts with a dot

        printf("File: %s\n", f->d_name);
    }
    closedir(dir);
}

score 4 · Answer 5 · answered Dec 19 '09 at 12:56

You have to use operating system calls (e.g. the Win32 API) or a wrapper around them. I tend to use Boost.Filesystem as it is superior interface compared to the mess that is the Win32 API (as well as being cross platform).

If you are looking to use the Win32 API, Microsoft has a list of functions and examples on msdn.

score 3 · Answer 6 · answered Nov 20 '08 at 22:19

If you're in Windows & using MSVC, the MSDN library has sample code that does this.

And here's the code from that link:

#include <windows.h>
#include <tchar.h> 
#include <stdio.h>
#include <strsafe.h>

void ErrorHandler(LPTSTR lpszFunction);

int _tmain(int argc, TCHAR *argv[])
{
   WIN32_FIND_DATA ffd;
   LARGE_INTEGER filesize;
   TCHAR szDir[MAX_PATH];
   size_t length_of_arg;
   HANDLE hFind = INVALID_HANDLE_VALUE;
   DWORD dwError=0;

   // If the directory is not specified as a command-line argument,
   // print usage.

   if(argc != 2)
   {
      _tprintf(TEXT("\nUsage: %s <directory name>\n"), argv[0]);
      return (-1);
   }

   // Check that the input path plus 2 is not longer than MAX_PATH.

   StringCchLength(argv[1], MAX_PATH, &length_of_arg);

   if (length_of_arg > (MAX_PATH - 2))
   {
      _tprintf(TEXT("\nDirectory path is too long.\n"));
      return (-1);
   }

   _tprintf(TEXT("\nTarget directory is %s\n\n"), argv[1]);

   // Prepare string for use with FindFile functions.  First, copy the
   // string to a buffer, then append '\*' to the directory name.

   StringCchCopy(szDir, MAX_PATH, argv[1]);
   StringCchCat(szDir, MAX_PATH, TEXT("\\*"));

   // Find the first file in the directory.

   hFind = FindFirstFile(szDir, &ffd);

   if (INVALID_HANDLE_VALUE == hFind) 
   {
      ErrorHandler(TEXT("FindFirstFile"));
      return dwError;
   } 

   // List all the files in the directory with some info about them.

   do
   {
      if (ffd.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
      {
         _tprintf(TEXT("  %s   <DIR>\n"), ffd.cFileName);
      }
      else
      {
         filesize.LowPart = ffd.nFileSizeLow;
         filesize.HighPart = ffd.nFileSizeHigh;
         _tprintf(TEXT("  %s   %ld bytes\n"), ffd.cFileName, filesize.QuadPart);
      }
   }
   while (FindNextFile(hFind, &ffd) != 0);

   dwError = GetLastError();
   if (dwError != ERROR_NO_MORE_FILES) 
   {
      ErrorHandler(TEXT("FindFirstFile"));
   }

   FindClose(hFind);
   return dwError;
}


void ErrorHandler(LPTSTR lpszFunction) 
{ 
    // Retrieve the system error message for the last-error code

    LPVOID lpMsgBuf;
    LPVOID lpDisplayBuf;
    DWORD dw = GetLastError(); 

    FormatMessage(
        FORMAT_MESSAGE_ALLOCATE_BUFFER | 
        FORMAT_MESSAGE_FROM_SYSTEM |
        FORMAT_MESSAGE_IGNORE_INSERTS,
        NULL,
        dw,
        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
        (LPTSTR) &lpMsgBuf,
        0, NULL );

    // Display the error message and exit the process

    lpDisplayBuf = (LPVOID)LocalAlloc(LMEM_ZEROINIT, 
        (lstrlen((LPCTSTR)lpMsgBuf)+lstrlen((LPCTSTR)lpszFunction)+40)*sizeof(TCHAR)); 
    StringCchPrintf((LPTSTR)lpDisplayBuf, 
        LocalSize(lpDisplayBuf) / sizeof(TCHAR),
        TEXT("%s failed with error %d: %s"), 
        lpszFunction, dw, lpMsgBuf); 
    MessageBox(NULL, (LPCTSTR)lpDisplayBuf, TEXT("Error"), MB_OK); 

    LocalFree(lpMsgBuf);
    LocalFree(lpDisplayBuf);
}

score 3 · Answer 7 · edited May 23 '17 at 12:10

I've just asked a similar question and here's my solution based on answer received (using boost::filesystem library):

#include <string>
#include <iostream>
#include <boost/filesystem.hpp>
using namespace std;
using namespace boost::filesystem;

int main()
{
    path p("D:/AnyFolder");
    for (auto i = directory_iterator(p); i != directory_iterator(); i++)
    {
        if (!is_directory(i->path())) //we eliminate directories in a list
        {
            cout << i->path().filename().string() << endl;
        }
        else
            continue;
    }
}

Output is like:

file1.txt
file2.dat

Roland Rabien · Answer 8 · 2008-11-20T21:18:03.937

2

Solving this will require a platform specific solution. Look for opendir() on unix/linux or FindFirstFile() on Windows. Or, there are many libraries that will handle the platform specific part for you.

edited Nov 20 '08 at 21:18

answered Nov 20 '08 at 19:25

Roland Rabien

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Jean Knapp · Answer 9 · 2018-06-17T20:55:03.637

After combining a lot of snippets, I finally found a reuseable solution for Windows, that uses ATL Library, which comes with Visual Studio.

#include <atlstr.h>

void getFiles(CString directory) {
    HANDLE dir;
    WIN32_FIND_DATA file_data;
    CString  file_name, full_file_name;
    if ((dir = FindFirstFile((directory + "/*"), &file_data)) == INVALID_HANDLE_VALUE)
    {
        // Invalid directory
    }

    while (FindNextFile(dir, &file_data)) {
        file_name = file_data.cFileName;
        full_file_name = directory + file_name;
        if (strcmp(file_data.cFileName, ".") != 0 && strcmp(file_data.cFileName, "..") != 0)
        {
            std::string fileName = full_file_name.GetString();
            // Do stuff with fileName
        }
    }
}

To access the method, just call:

getFiles("i:\\Folder1");

@NadavB it uses atlstr.h library, which I believe is only for Windows. — Jean Knapp, Jun 17 '18 at 20:57

score 0 · Answer 10 · edited Sep 13 '13 at 07:47

0

Or you do this and then read out the test.txt:

#include <windows.h>

int main() {    
system("dir /b > test.txt");
}

The "/b" means just filenames are returned, no further info.

edited Sep 13 '13 at 07:47

Community

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answered Jul 02 '13 at 23:41

Enders

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This looks really nice and easy, but I don't get how to use this. Could you explain what is `/b` and where will we give the directory? – smttsp Jul 27 '13 at 11:26

score 0 · Answer 11 · edited Sep 13 '13 at 07:48

0

HANDLE WINAPI FindFirstFile(
  __in   LPCTSTR lpFileName,
  __out  LPWIN32_FIND_DATA lpFindFileData
);

Setup the attributes to only look for directories.

edited Sep 13 '13 at 07:48

Mat

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answered Dec 19 '09 at 12:59

kenny

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mystack · Answer 12 · 2014-07-03T09:56:39.250

You can use the following code for getting all files in a directory.A simple modification in the Andreas Bonini answer to remove the occurance of "." and ".."

CString dirpath="d:\\mydir"
DWORD errVal = ERROR_SUCCESS;
HANDLE dir;
WIN32_FIND_DATA file_data;
CString  file_name,full_file_name;
if ((dir = FindFirstFile((dirname+ "/*"), &file_data)) == INVALID_HANDLE_VALUE)
{
    errVal=ERROR_INVALID_ACCEL_HANDLE;
    return errVal;
}

while (FindNextFile(dir, &file_data)) {
    file_name = file_data.cFileName;
    full_file_name = dirname+ file_name;
    if (strcmp(file_data.cFileName, ".") != 0 && strcmp(file_data.cFileName, "..") != 0)
    {
        m_List.AddTail(full_file_name);
    }
}

score -1 · Answer 13 · edited May 06 '14 at 23:51

void getFilesList(String filePath,String extension, vector<string> & returnFileName)
{
    WIN32_FIND_DATA fileInfo;
    HANDLE hFind;   
    String  fullPath = filePath + extension;
    hFind = FindFirstFile(fullPath.c_str(), &fileInfo);
    if (hFind == INVALID_HANDLE_VALUE){return;} 
    else {
        return FileName.push_back(filePath+fileInfo.cFileName);
        while (FindNextFile(hFind, &fileInfo) != 0){
            return FileName.push_back(filePath+fileInfo.cFileName);}
        }
 }


 String optfileName ="";        
 String inputFolderPath =""; 
 String extension = "*.jpg*";
 getFilesList(inputFolderPath,extension,filesPaths);
 vector<string>::const_iterator it = filesPaths.begin();
 while( it != filesPaths.end())
 {
    frame = imread(*it);//read file names
            //doyourwork here ( frame );
    sprintf(buf, "%s/Out/%d.jpg", optfileName.c_str(),it->c_str());
    imwrite(buf,frame);   
    it++;
 }

you have 2 returns in method getFilesList, the code after the return FileName.push_back(filePath+fileInfo.cFileName); is not reachable — mmohab, May 06 '14 at 23:50

How do I get a list of files in a directory in C++?

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