File count in a directory using C++

Question

How do I get the total number of files in a directory by using C++ standard library? Any help is appreciated.

Answer 1

You can't. The closest you are going to be able to get is to use something like Boost.Filesystem

Answer 2

You would need to use a native API or framework.

Answer 3

If you don't exclude the basically always available C standard library, you can use that one. Because it's available everywhere anyways, unlike boost, it's a pretty usable option!

An example is given here.

And here:

#include <stdio.h>
#include <sys/types.h>
#include <dirent.h>

int main (void)
{
  DIR *dp;
  int i;
  struct dirent *ep;     
  dp = opendir ("./");

  if (dp != NULL)
  {
    while (ep = readdir (dp))
      i++;

    (void) closedir (dp);
  }
  else
    perror ("Couldn't open the directory");

  printf("There's %d files in the current directory.\n", i);

  return 0;
}

And sure enough

 > $ ls -a | wc -l
138
 > $ ./count
There's 138 files in the current directory.

This isn't C++ at all, but it is available on most, if not all, operating systems, and will work in C++ regardless.

UPDATE: I'll correct my previous statement about this being part of the C standard library - it's not. But you can carry this concept to other operating systems, because they all have their ways of dealing with files without having to grab out additional libraries.