How can I get the 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, 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, we can write a program to display all the files and folders in a directory.

Syntax

DIR *opendir(const char *dirname);
struct dirent *readdir(DIR *dirp);
int closedir(DIR *dirp);

Algorithm

Following is the algorithm to get the list of files in a directory using C −

Begin
   Declare a pointer 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.

Example: List Files in Current Directory

This program opens the current folder and prints the names of all files and subfolders inside it −

#include <stdio.h>
#include <dirent.h>

int main() {
    DIR *dr;
    struct dirent *en;
    
    dr = opendir("."); // open current directory
    if (dr) {
        printf("Files and directories in current folder:\n");
        while ((en = readdir(dr)) != NULL) {
            printf("%s\n", en->d_name); // print directory/file name
        }
        closedir(dr); // close directory
    } else {
        printf("Could not open directory\n");
    }
    return 0;
}

Files and directories in current folder:
.
..
main.c
notes.txt
images
data.csv

Example: List Files in Specific Directory

This program lists files in a specified directory path −

#include <stdio.h>
#include <dirent.h>

int main() {
    DIR *dr;
    struct dirent *en;
    char path[] = "/tmp"; // specify directory path
    
    dr = opendir(path);
    if (dr) {
        printf("Files in %s directory:\n", path);
        while ((en = readdir(dr)) != NULL) {
            // Skip . and .. entries
            if (en->d_name[0] != '.') {
                printf("%s\n", en->d_name);
            }
        }
        closedir(dr);
    } else {
        printf("Could not open directory: %s\n", path);
    }
    return 0;
}

Files in /tmp directory:
temp_file.txt
cache_data
log_file.log

Key Points

• opendir() returns NULL if the directory cannot be opened
• readdir() returns NULL when no more entries are available
• Always call closedir() to free allocated resources
• The entries "." (current dir) and ".." (parent dir) are included in the listing
• Use dirent.h header for directory operations in C

Conclusion

Directory listing in C uses the opendir(), readdir(), and closedir() functions. Always check if opendir() succeeds before reading entries and remember to close the directory when done.