Flat inheritance

static.cpp

#include <iostream>
using namespace std;

struct A
{
	int p_value;
	void print() { cout << "Value = \"" << p_value << "\"." << endl; }
};

template < typename T >
struct B
{
	void do_b(T& base) { base.p_value = 99; }
};

template < typename T >
struct C
{
	void do_c(T& base) { base.p_value = 11; }
};

template < typename A, template<typename> class B, template<typename> class C >
struct D : public A, protected B<A>, protected C<A>
{
	void do_b() { B<A>::do_b(*this); }
	void do_c() { C<A>::do_c(*this); }
};

int main()
{
	D<A,B,C> x;
	x.do_b();
	x.print();
	x.do_c();
	x.print();
}

virtual.cpp

#include <iostream>
using namespace std;

struct A
{
	int p_value;
	void print() { cout << "Value = \"" << p_value << "\"." << endl; }
};

struct B : virtual public A
{
	void do_b() { p_value = 99; }
};

struct C : virtual public A
{
	void do_c() { p_value = 11; }
};

struct D : public B, public C
{
};

int main()
{
	D x;
	x.do_b();
	x.print();
	x.do_c();
	x.print();
}