C :: Program That Allows To See Contents Of Sub Folders

I do not have much experience in C. I'm trying to create a C program that allows me to see the contents of subfolders.

For example. introducing the argument folder C: images

However, this folder has sub folders with images inside.

C: images 1
C: images 1 FronA.jpg
C: images 1 FronB.jpg
....

my idea is to list the files from the root folder introduced in the argument parameter.

I am using the following code,

My problem is when try read de sub-folder, give every time the ".",

DIR *dir2 = opendir(path);
struct dirent *entry2 = readdir(dir2);

Code:

int main(int argc, char** argv) {
char dir_name[256];
char sub_dir_name[256];
char filename_ext[256]; //Extension file name
DIR *d;
struct dirent *sub_dir;

[Code]...