/*
** $Id: enum.c 802 2008-03-01 19:26:43Z phf $
**
** Basic enumeration types, not much to say about these,
** except for "Please use them if appropriate." I guess?
*/

#include <stdio.h>
#include <stdlib.h>

#define ONE 1
#define TWO 2

const int one = 1;
const int two = 2;

enum bla { eins = 1, zwei = 2 }; // explicit values
enum xyz { a, b, c }; // implicit values starting at 0
enum pop { q=12, o, f, p=12, t, m }; // strange but allowed...

int x = ONE; // works since textual substitution by preprocessor
//int y = one; // doesn't work since const int is not really const... :-/
int z = eins; // works, so enum is a good replacement for #define

int main(void)
{
  // just to show off the values, check the last one especially!
  printf( "%d %d %d\n", ONE, one, eins );
  printf( "%d %d %d\n", a, b, c );
  printf( "%d %d %d %d %d %d\n", q, o, f, p, t, m);

  // we can use enums as type for variables, but unlike in Pascal
  // we don't get much help from the compiler restricting possible
  // values we can assign :-/ however, using an enum type still is
  // good style and documents your intention of only allowing some
  // values but not others; you can also use an assertion to make
  // sure of course

  enum bla x; // aside: shadows global x...

  x = eins; // should work, that's how enum bla is defined
  x = zwei; // again
  x = 0xAFFE; // shouldn't be valid, but it's not checked... :-/

  // assignment from enums to ints are allowed, and sadly the
  // reverse is true as well... :-/

  int z; // aside: shadows global z...

  z = x; // good
  x = z; // not so good, again no range check

  return EXIT_SUCCESS;
}