C++ method to traverse the folder directory

1. Method 1: VS2019

// dirlist.cpp :  Defines the entry point for the console application. 

//#include "stdafx.h"
#include <string>
#include <io.h>
#include <vector>
#include <iostream>

using namespace std;

/************************************************************************/
/*  Gets all file names under the folder 
 Input: 
path :  Folder path 
exd :   The filename suffix to obtain, for example jpg , png And so on; If you want to get all of them 
 The file name , exd = "" or "*"
 Output: 
files :  Gets a list of file names 
shao, 20140707
*/
/************************************************************************/
void getFiles(string path, string exd, vector<string>& files)
{
 //cout << "getFiles()" << path<< endl; 
 // File handle 
 long  hFile = 0;
 // File information 
 struct _finddata_t fileinfo;
 string pathName, exdName;

 if (0 != strcmp(exd.c_str(), ""))
 {
 exdName = "\\*." + exd;
 }
 else
 {
 exdName = "\\*";
 }

 if ((hFile = _findfirst(pathName.assign(path).append(exdName).c_str(), &fileinfo)) != -1)
 {
 do
 {
  //cout << fileinfo.name << endl; 

  // If it's a folder, it still has folders in it , The iteration of the 
  // If it is not , Join the list 
  if ((fileinfo.attrib & _A_SUBDIR))
  {
  if (strcmp(fileinfo.name, ".") != 0 && strcmp(fileinfo.name, "..") != 0)
   getFiles(pathName.assign(path).append("\\").append(fileinfo.name), exd, files);
  }
  else
  {
  if (strcmp(fileinfo.name, ".") != 0 && strcmp(fileinfo.name, "..") != 0)
   files.push_back(pathName.assign(path).append("\\").append(fileinfo.name));
  }
 } while (_findnext(hFile, &fileinfo) == 0);
 _findclose(hFile);
 }
}

void main()
{
 cout << "start list" << endl;
 vector<string> files;
 const char* filePath = "D:\\opencv_4.1.0\\newbuild\\install\\x64\\vc16\\lib";

 // Gets all under the path jpg file 
 //getFiles(filePath, "jpg", files);

 // Gets all under the path lib file 
 getFiles(filePath, "lib", files);

 // List file output path 
 FILE* fp;
 fopen_s(&fp, "d:\\dir_list.txt", "w");

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

 fputs(files[i].c_str(), fp);
 fputs("\n", fp);

 }
 fclose(fp);

 cout << "end list" << endl;
 getchar();

}

Method 2: CMD

win+r brings up the Run window and outputs cmd
Type: cd /d D:\ opencv_4.1.0 \newbuild\install\x64\vc16\lib enter (fill in your own path)
Input: dir /b *.lib * > 0. txt enter