/*
** $Id: macros.c 802 2008-03-01 19:26:43Z phf $
**
** Some examples of preprocessor macros. Macros can
** be a pain to use correctly, and while they "look
** like" functions they don't behave anything like
** functions. Unless you desperately need them, I'd
** stay away. But you must be able to *read* macros
** in other people's code of course... :-/
*/

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

#define ONE 1
#define TWO 2

#define PLUSONE(x) (x+1)

#define MAX(x,y) (x>y ? x : y)
// often it is a good idea to surround each
// parameter with parenthesis to make sure
// nothing goes wrong...
#define BMAX(x,y) ((x)>(y) ? (x) : (y))
#define VOODOO(x) (x++)

// unless NDEBUG is set, print debugging messages
// (NDEBUG is also used by assert.h and assert())
#ifndef NDEBUG
#define DEBUG(x) printf("DEBUG: %s\n", x);
#else
#define DEBUG(x) 
#endif

int main( void )
{
  int a = ONE;
  int b = PLUSONE(a);

  printf("a=%d, b=%d\n", a, b);
  printf("%d\n", a<b?b:a);
  printf("a=%d, b=%d\n", a, b);
  printf("%d\n", MAX(a,b));
  printf("a=%d, b=%d\n", a, b);
  printf("%d\n", MAX(a++,b++)); // => (a++<b++?b++:a++)
  printf("a=%d, b=%d\n", a, b);

  int c = VOODOO(b);
  printf("b=%d, c=%d\n", b, c);

  DEBUG("Peter was here... :-)");

  return EXIT_SUCCESS;
}