Polymorphic C

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

typedef struct	s_main {
	void	(*f)(void);
}		t_main;

typedef struct	s_c1 {
	void	(*f)(void);
	int	padding;
	int	pad;
}		c1;

typedef struct	s_c2 {
	void	(*f)(void);
	void	(*g)(const char *);
}		c2;

void	f(){
	printf("f called\n");
}

void	f2(){
	printf("f2 on board\n");
}

void	g(const char* s){
	printf("g called with %s\n", s);
}

t_main	*new_main(){
	t_main	*ret = malloc(sizeof(t_main));

	ret->f = (f);
	return ret;
}

t_main	*new_c1(){
	c1 	*ret = malloc(sizeof(c1));

	ret->f = (f);
	ret->padding = 10;
	ret-> pad = 0;
	return (t_main*)ret;
}

t_main	*new_c2(){
	c2	*ret = malloc(sizeof(c2));

	ret->f = (f2);
	ret->g = (g);
	return (t_main*)ret;
}

int main(){
	t_main	*a, *b, *c;
	c1*	e;
	c2*	d;

	a = new_main();
	b = new_c1();
	c = new_c2();
	d = (c2*)c;
	e = (c1*)b;
	a->f();
	b->f();
	c->f();
	d->g("test");
	printf("%d\n", e->padding);
	return 0;
}

/** stdout result
f called
f called
f2 on board
g called with test
10
*/