point.r

Object-Oriented Programming With ANSI-C这本书中的源代码!找了很久

#ifndef	POINT_R
#define	POINT_R

struct Point {
	const void * class;
	int x, y;				/* coordinates */
};

#define	x(p)	(((const struct Point *)(p)) -> x)
#define	y(p)	(((const struct Point *)(p)) -> y)

#endif