Get List of Files in a Directory Using C or C++

Listing files in a directory is used to write a program that opens a specified folder (e.g: "/myfiles"), reads its contents, and displays the names of each file and subfolder one by one.

In C/C++, to see all the files in a directory, you can use special system functions that let you read the directory's contents.

In real life, we open folder to see the contents inside the files. Similarly, in C or C++, we can write a program to display all the files and folders in a directory.

Algorithm

Following is the algorithm to get the list of files in a directory using C/C++.

Begin
   Declare a poniter dr to the DIR type.
   Declare another pointer en of the dirent structure.
   Call opendir() function to open all file in present directory.
   Initialize dr pointer as dr = opendir(".").
   If(dr)
      while ((en = readdir(dr)) != NULL)
         print all the file name using en->d_name.
      call closedir() function to close the directory.
End.

C/C++ Programs to Get List of Files in a Directory

To get list of files in a directory, we open the current folder and prints the names of all files inside it.

Let us assume that the current directory contains the following files and folders as main.cpp, notes.txt, images(folder) and data.csv.

Let us have an clear idea about the program step by step in C/C++:

• step 1: Open the directory using opendir().
• step 2: Read each entry (file/folder) using readdir() inside a loop.
• step 3: Print the name of each entry using en->d_name.
• step 4: Close the directory using closedir().

Example

This program opens the current folder and prints the names of all files and subfolders inside it, one by one.

#include <stdio.h>
#include <dirent.h>
int main(void) {
   DIR *dr;
   struct dirent *en;
   dr = opendir("."); //open all or present directory
   if (dr) {
      while ((en = readdir(dr)) != NULL) {
         printf("%s\n", en->d_name); //print all directory name
      }
      closedir(dr); //close all directory
   }
   return(0);
}

main.cpp
notes.txt
images
data.csv

No such file or directory

#include <iostream>
#include <dirent.h>
#include <sys/types.h>
using namespace std;
int main(void) {
   DIR *dr;
   struct dirent *en;
   dr = opendir("."); //open all directory
   if (dr) {
      while ((en = readdir(dr)) != NULL) {
         cout<<" \n"<<en->d_name; //print all directory name
      }
      closedir(dr); //close all directory
   }
   return(0);
}

main.cpp
notes.txt
images
data.csv

No such file or directory

C++ Program to List All Files in a Directory Using <filesystem>

In C++17, a new header called <filesystem> was introduced that makes the program easy to work with files and directories. Instead of using older system-based functions like opendir() and readdir().

Example

This program uses C++17's <filesystem> to open the current folder and print the name of each file and subfolder inside it.

#include<iostream>
#include<filesystem> // C++17 feature
namespace fs = std::filesystem;
int main(){
   std::string path = "."; // Current directory
   for(const auto&entry:fs::directory_iterator(path)) {
       std::cout<<entry.path().filename()<<std::endl; 
   }
   return 0;
}

If the files exists, the output will be

main.cpp
notes.txt
images
data.csv

If the files doesn't exists(empty directory), the output will be

No such file or directory

This <filesystem> feature is only available in C++17 and does not exist in C. As it is not part of C, so for similar functionality in C, you have to rely on OS-specific methods.