virtual functions in C

#include <stdio.h>

typedef struct Class
{
    const struct Class* parent;
    void (*virtualPrint)(void*);
} Class;

typedef struct A
{
    const Class* class;
    int a;
} A;

typedef struct B
{
    const Class* class;
    A a;
    int b;
} B;

static const Class* getClass(void* this)
{
    return *(Class**)this;
}

static void virtualPrintA(void* this)
{
    A* a = this;
    printf("virtualPrintA: %d\n", a->a);
}

static void virtualPrintB(void* this)
{
    B* b = this;
    getClass(&b->a)->virtualPrint(&b->a);

    printf("virtualPrintB: %d\n", b->b);
}

static const Class aClass = {.parent = NULL, .virtualPrint = virtualPrintA};
static const Class bClass = {.parent = &aClass, .virtualPrint = virtualPrintB};

int main()
{
    A a = {.class = &aClass, .a = 1};
    B b = {.class = &bClass, .a = {.class = &aClass, .a = 2}, .b = 3};
    A* c = (A*)&b;

    getClass(&a)->virtualPrint(&a);
    getClass(&b)->virtualPrint(&b);
    getClass(c)->virtualPrint(c);

    return 0;
}