Basic vtables for emulate OOP

oop.c

#include <stdio.h>
#define Method(x, y, type) ((type)(x->methods[y] ))(x)

#pragma pack(1) 
typedef struct {
    void* space;
    void** methods;
    size_t size;
    int methods_size;
} table;


table* Animal(char* a, char* (*eat) (struct table* self)) {
    table* animal = malloc(sizeof(table));
    animal->space = malloc(256);
    animal->size = 256;
    memcpy(animal->space, a, strlen(a)+1);
    animal->methods = malloc(sizeof(void*));
    animal->methods[0] = eat;
    animal->methods_size = 1;
    return animal;
}

table* Wolf(table* animal, char* a, char* (sound) (struct table* self)) {
    memcpy(animal->space, a, strlen(a)+1);
    animal->methods_size++;
    animal->methods = realloc(animal->methods, animal->methods_size*sizeof(void*));
    animal->methods[1] = sound;
    return animal;
}

table* Dog(table* wolf, char* a, char* (sound) (struct table* self)) {
    memcpy(wolf->space, a, strlen(a)+1);
    wolf->methods_size++;
    wolf->methods = realloc(wolf->methods, wolf->methods_size*sizeof(void*));
    wolf->methods[2] = sound;
    return wolf;
}

int main()
{
    void eat(table* self) {
        printf("I am a %s\n", (char*)self->space);
    }
        
    table* animal = Animal("Animal", eat);
    Method(animal, 0, void (*) (table* self));
    
    void howl(table* self) {
        printf("howww\n");
    }
            
    table* wolf = Wolf(animal, "Wolf", howl);
    Method(wolf, 0, void (*) (table* self));
    Method(wolf, 1, void (*) (table* self));

    void bark(table* self) {
        printf("au au");
    }
    
    table* dog = Dog(wolf, "Dog", bark);
    Method(dog, 0, void (*) (table* self));
    Method(dog, 1, void (*) (table* self)); // A dog can also howl
    Method(dog, 2, void (*) (table* self));

    return 0;
}