#include <grp.h>

#include <pwd.h>

#include <sys/types.h>

#include <unistd.h>

#include <stdlib.h>

#include <stdio.h>

int

main (int argc, char *argv[])

{

  uid_t me;

  struct passwd *my_passwd;

  struct group *my_group = NULL;

  char **members;

  me = getuid ();

  my_passwd = getpwuid (me);

  if (my_passwd == NULL)

    printf ("Cannot find user entry for UID %d\n", me);

  else

    {

      printf ("My login name is %s.\n", my_passwd->pw_name);

      printf ("My uid is %d.\n", (int)(my_passwd->pw_uid));

      printf ("My home directory is %s.\n", my_passwd->pw_dir);

      printf ("My default shell is %s.\n", my_passwd->pw_shell);

      my_group = getgrgid (my_passwd->pw_gid);

      if (my_group == NULL)

	printf ("No data for group %d found\n", my_passwd->pw_gid);

      else

	{

	  printf ("My default group is %s (%d).\n",

		  my_group->gr_name, (int)(my_passwd->pw_gid));

	  printf ("The members of this group are:\n");

	  for (members = my_group->gr_mem; *members != NULL; ++members)

	    printf ("  %s\n", *members);

	}

    }

  return my_passwd && my_group ? EXIT_SUCCESS : EXIT_FAILURE;

}