#define debug(...)      fprintf(stderr, __VA_ARGS__)
#define showlist(...)   puts(#__VA_ARGS__)
#define report(test, ...) ((test)?puts(#test):\
            printf(__VA_ARGS__))

debug("Flag");
debug("X = %d\n", x);
showlist(The first, second, and third items.);
report(x>y, "x is %d but y is %d", x, y);
