Printing all the directories using c++ - c++

Question

This program is printing the directories at the root level
Directory_1
Directory_2
but I want to be able to print the directories within them too
Directory_1
Directory_1_2
Directory_1_3
Directory_2
Directory 2_1
Directory_2_1_1
Directory_4
I am trying to do it recursively but I am finding it hard to pass the Directory_1 as a root so it gets evaluated.. What am i missing?
Here is my output
..
.
Directory_1
Directory_2
Failed to open directory: No such file or directory
Code
#include <dirent.h>
#include <errno.h>
#include <stdio.h>
#include <sys/stat.h>
char *arg_temp;
int printDepthFirst(char *arg_tmp);
int main(int argc, char *argv[]) {
if (argc != 2) {
fprintf(stderr, "Usage: %s directory_name\n", argv[0]);
return 1;
}
arg_temp = argv[1];
printDepthFirst(arg_temp);
}
int printDepthFirst(char *arg_tmp)
{
struct dirent *direntp;
DIR *dirp;
if ((dirp = opendir(arg_tmp)) == NULL) {
perror ("Failed to open directory");
return 1;
}
while ((direntp = readdir(dirp)) != NULL)
{
printf("%s\n", direntp->d_name);
arg_tmp = direntp->d_name;
}
printDepthFirst(arg_tmp);
while ((closedir(dirp) == -1) && (errno == EINTR)) ;
return 0;
}
Now, I know some people get irritated when asking questions that they think I am expecting them to code this, you dont need to, if you can tell me theoretically what i need to do.. I will research it although if its a small programmatically fix and you can post that I would really appreaciate it.. but if not.. I would also love to hear about what needs to be done in words..
Thank you

Answer 1

Well this should help:
#define _XOPEN_SOURCE 500
#include <ftw.h>
#include <stdio.h>
static int display_info(const char *fpath, const struct stat *sb,
int tflag, struct FTW *ftwbuf)
{
switch(tflag)
{
case FTW_D:
case FTW_DP: puts(fpath); break;
}
return 0; /* To tell nftw() to continue */
}
int main(int argc, char *argv[])
{
if (argc != 2) {
fprintf(stderr, "Usage: %s directory_name\n", argv[0]);
return 1;
}
int flags = FTW_DEPTH | FTW_MOUNT | FTW_PHYS;
if (nftw(argv[1], display_info, 20, flags) == -1)
{
perror("nftw");
return 255;
}
return 0;
}

Answer 2

Have a look at what fields struct dirent contains.

Answer 3

The string dirent::d_name is a name of a directory, not it's full path. So, if your directory "C:\Alpha" contains directory "C:\Alpha\Beta", d_name would only contatin "Beta", not "C:\Alpha\Beta". You will have to assemble the full path yourself - appending slash/backslash to your arg_tmp and then appending new directory name, like this:
while ((direntp = readdir (dirp)) != NULL)
{
char *dirname = direntp->d_name;
// Only work with directories and avoid recursion on "." and "..":
if (direntp->d_type != DT_DIR || !strcmp (dirname, ".") || !strcmp (dirname, "..")) continue;
// Assemble full directory path:
char current [strlen (arg_tmp) + 2 + strlen (dirname)];
strcpy (current, arg_tmp);
strcat (current, "\\"); // Replace "\\" with "/" on *nix systems
strcat (current, dirname);
// Show it and continue:
printf ("%s\n", current);
printDepthFirst (current);
}
Also, you should call recursively inside the loop, not outside.

Answer 4

Inside your while loop inside printDepthFirst you might need something like:
if(direntp->d_type == DT_DIR)
printDepthFirst(directp->d_name);
You might perhaps have to worry about .. directories too.
Alternatively, I've found boost::filesystem to work quite well.