This shows the sub-directories in the current path.

It's not a lot different to something like…

  ls-l | grep ^d | cut xxx

Where xxx is the position of the filename but unlike the shell code, it isn't subject to the vagaries of the ls command.

 /* ---------------------------------------------
    Name: sdr
    Purpose: Displays the directories subservient
             to the current directory.
    ------------------------------------------ */
 
 #include <stdio.h>
 #include <dirent.h>
 #include <sys/types.h>
 #include <sys/stat.h>
 
 main(int argc, char *argv[]){
 
   char *DirectoryName;
   DIR *ThisDirectory;          /* List of directory contents */
   struct dirent *ThisEntry;    /* Entries in the directory list */
   struct stat ThisEntryStatus; /* Directory status entries */
 
   switch (argc)
   {
      case 1: DirectoryName = (char *)".";
              break;
      default: printf("sdr must be invoked from within the desired path.\n");
              break;
   }
 
   if((ThisDirectory = opendir(DirectoryName)) == NULL)
   {
     printf("'%s' is not a valid path \n", DirectoryName);
      return(1);
   }
 
   /* ------------------------------------------------------------
      Loop through the struct pulling out a pointer
      to a directory entry on each pass.
      Put this entry into a ThisEntryStatus struct
      and if that succeeds, check to see if this is a directory.
      If it is, check that it isn't the current (.) or parent (..)
      entry. if not, print the directory name...
      --------------------------------------------------------- */
   while (ThisEntry = readdir(ThisDirectory))
   {
      if (stat(ThisEntry->d_name, &ThisEntryStatus) == 0)
         if (ThisEntryStatus.st_mode & S_IFDIR)
            if (strcmp(ThisEntry->d_name, ".") != 0)
               if (strcmp(ThisEntry->d_name, "..") != 0)
                   printf("%s\n", ThisEntry->d_name);
   }
   return closedir(ThisDirectory);
 }