gistfile1.c

#ifndef OBJECT_H_
#define OBJECT_H_

#define OBJECT_INHERIT \
	void *(**vtable)(); \
	const char *name;
typedef struct object {
	OBJECT_INHERIT
} OBJECT;
enum
{
	CALL__print
};
extern void *(*OBJECT__vtable[])();
static void OBJECT__print(OBJECT *object);
extern OBJECT* new_object(const char *);
extern void print(void *object);
#endif


#ifndef PERSON_H_
#define PERSON_H_
#include "object.h"
typedef struct person {
	OBJECT_INHERIT
	int day;
	int month;
	int year;
} PERSON;
extern void *(*PERSON__vtable[])();
extern PERSON *new_person(const char *, int, int, int);
static void PERSON__print(PERSON *);
#endif


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

void *(*OBJECT__vtable[])() = {(void*(*)())&OBJECT__print};

void OBJECT__print(OBJECT *this)
{
	printf("(OBJECT) { name : \"%s\" }\n", this->name);		
}

void print(void *object)
{
	((OBJECT *)object)->vtable[CALL__print]((OBJECT *)object);
}

OBJECT* new_object(const char *name)
{
	OBJECT *object = (OBJECT *)malloc(sizeof(OBJECT));
	object->vtable = OBJECT__vtable;
	object->name = name;
	return object;
}


#include "person.h"
#include "object.h"
#include <stdlib.h>
#include <stdio.h>

void *(*PERSON__vtable[])() = {(void*(*)())&PERSON__print};

PERSON *new_person(const char *name, int day, int month, int year)
{
	OBJECT *super;
	PERSON *this;

	super = new_object(name);
	this = (PERSON *)realloc(super, sizeof(PERSON));

	this->vtable = PERSON__vtable;
	this->day = day;
	this->month = month;
	this->year = year;

	return this;
}

void PERSON__print(PERSON *this)
{
	printf("(PERSON) { name : \"%s\", day : %d, month : %d, year : %d }\n",
		this->name, this->day, this->month, this->year);
}




#include "object.h"
#include "person.h"
#include <stdlib.h>

int main(int argc, char const* argv[])
{
	OBJECT *spoon;
	PERSON *arian;

	spoon = new_object("Spoon");
	if(spoon == NULL) return 1;

	arian = new_person("Arian", 28, 11, 1993);
	if(arian == NULL) return 1;

	print(spoon);
	print(arian);

	free(spoon);
	free(arian);
	return 0;

	/* OUTPUT
	(OBJECT) { name : "Spoon" }
	(PERSON) { name : "Arian", day : 28, month : 11, year : 1993 }
	*/
}