Size of classes with and without a vtable

size_vtable.cpp

#include <iostream>

struct A
{
};

struct B : A
{
};

struct Bv : virtual A
{
};

struct C : A
{
};

struct Cv : virtual A
{
};

struct D : B, C
{
};

struct Dv : virtual B, virtual C
{
};

#define PRINT(T) std::cout << "size of " #T " is:\t" << sizeof(T) << std::endl;

int main()
{
    PRINT(A);
    PRINT(B);
    PRINT(Bv);
    PRINT(C);
    PRINT(Cv);
    PRINT(D);
    PRINT(Dv);

    return 0;
}