#include <stdio.h>

#define DUMB_ZERO(X) ((X)-(X))

int val = -33;

int
dumb ()
{
  return val++;
}

int TODAY_IS_THURSDAY = 1;
#define VERIFY(EXP) do { if (! (EXP)) { fprintf (stderr, "*** Failed to verify that %s on line %d of %s\n", #EXP, __LINE__, __FILE__); } } while (0)

int
main (int argc, char *argv[])
{
  printf ("val was %d\n", val);
  printf ("DUMB_ZERO(val++) = %d\n", DUMB_ZERO(val++));
  printf ("DUMB_ZERO(dumb()) = %d\n", DUMB_ZERO(dumb()));
  printf ("val is now %d\n", val);
  VERIFY(val > 0);
  if (TODAY_IS_THURSDAY)
    VERIFY(val > 0);
  else
    printf ("On other days, we vote for hoodies.\n");
}