Find All Files In Directory C++

GetFilesInDirectory

#include <iostream>
#include <vector>
#include <string>
#include <fstream>
#include <windows.h>

using namespace std;

void GetFilesInDirectory(std::vector<string> &out, const string &directory, bool getFolderNames)
{
    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 && !getFolderNames)
            continue;

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

    FindClose(dir);
}

int main() {
    vector<string> files;
    GetFilesInDirectory(files, "", true);

    for( int i = 0; i < files.size(); i++ ) {
        cout << files[i] << endl;
    }
    return 0;
}

Thank you!