gistfile1.c

#include <stdio.h>
#include <sys/types.h>
#include <sys/dir.h>
#include <dirent.h>
#include <unistd.h>
#include <string.h>

void find_dir(char *path, char *dir);

int main(int argc, char *argv[])
{
  char dir[100];

  if (argc != 2)
  {
    getcwd(dir, sizeof(dir));
  } else {
    strncpy(dir, argv[1], sizeof(dir) - 1);
  }

  find_dir(dir, "");
  return 0;
}

void find_dir(char *path, char *dir)
{
  char full_path[150];
  struct dirent *entry;
  DIR *current_dir;

  snprintf(full_path, sizeof(full_path) - 1, "%s%s/", path, dir);
  current_dir = opendir(full_path);
  while ((entry = readdir(current_dir)) != NULL)
  {
    if ((entry->d_type == 4) && strcmp(entry->d_name, ".") && strcmp(entry->d_name, ".."))
    {
      printf("%s%s\n", full_path, entry->d_name);
      find_dir(full_path, entry->d_name);
    }
  }
  closedir(current_dir);
}