How to get the number of files in the specific folder using C or C++ function?

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count number of files with a given extension in a directory - C++?

How to get the number of files in the specific folder using c or c++ function? Is there any c library function that could get the number of files in a given directory?

Here is a working example of opendir/readdir/closedir use (no recursion here):

void listdir(char *dir) {
  struct dirent *dp;
  DIR *fd;

  if ((fd = opendir(dir)) == NULL) {
    fprintf(stderr, "listdir: can't open %s\n", dir);
    return;
  }
  while ((dp = readdir(fd)) != NULL) {
  if (!strcmp(dp->d_name, ".") || !strcmp(dp->d_name, ".."))
    continue;    /* skip self and parent */
  printf("%s/%s\n", dir, dp->d_name);
  }
  closedir(fd);
}