/* The following code example is taken from the book * "C++ Templates - The Complete Guide" * by David Vandevoorde and Nicolai M. Josuttis, Addison-Wesley, 2002 * * (C) Copyright David Vandevoorde and Nicolai M. Josuttis 2002. * Permission to copy, use, modify, sell and distribute this software * is granted provided this copyright notice appears in all copies. * This software is provided "as is" without express or implied * warranty, and with no claim as to its suitability for any purpose. */#include <iostream>class NotVirtual {};class Virtual {  public:    virtual void foo() {    }};template <typename VBase>class Base : private VBase {  public:    // the virtuality of foo() depends on its declaration    // (if any) in the base class VBase    void foo() {       std::cout << "Base::foo()" << '\n';    }};template <typename V>class Derived : public Base<V> {  public:    void foo() {       std::cout << "Derived::foo()" << '\n';    }};int main(){    Base<NotVirtual>* p1 = new Derived<NotVirtual>;    p1->foo();  // calls Base::foo()    Base<Virtual>* p2 = new Derived<Virtual>;    p2->foo();  // calls Derived::foo()}