Write a C program to print all files and folders.

In C programming, we can list all files and folders in a directory using directory handling functions. This requires the dirent.h header which provides structures and functions to work with directory entries.

Syntax

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

Key Functions

• opendir() − Opens a directory stream for reading
• readdir() − Reads directory entries one by one
• closedir() − Closes the directory stream

Note: This program uses dirent.h which is POSIX standard. On Windows with certain compilers, you might need additional setup or use platform-specific alternatives.

Example

Following is the C program for printing all files and folders in the current directory −

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

int main() {
    struct dirent *d;
    DIR *dr;
    
    dr = opendir(".");
    
    if(dr != NULL) {
        printf("List of Files & Folders:
");
        printf("-------------------------
");
        
        while((d = readdir(dr)) != NULL) {
            printf("%s
", d->d_name);
        }
        
        closedir(dr);
    }
    else {
        printf("Error: Could not open directory!
");
    }
    
    return 0;
}

How It Works

1. opendir(".") opens the current directory ("." represents current directory)
2. readdir() reads each directory entry sequentially until it returns NULL
3. d->d_name contains the name of each file or folder
4. closedir() releases the directory stream resources

Sample Output

List of Files & Folders:
-------------------------
.
..
program.c
data.txt
folder1
image.jpg
script.py

Key Points

• The entries "." and ".." represent current and parent directories respectively
• Always check if opendir() returns NULL to handle errors
• Remember to call closedir() to free system resources
• The order of files listed depends on the filesystem implementation

Conclusion

Using dirent.h functions, we can easily traverse directory contents in C. This approach provides a portable way to list files and folders across different Unix-like systems.