#include <iostream> #include <vector> #include <algorithm> class A { public: A() {} virtual void whoami() const { std::cout<<"I am an instance of A"<<std::endl; } virtual ~A() {} }; class B : public A { public: B() : A() {} void whoami() const override { std::cout<<"I am an instance of B"<<std::endl; } ~B() {} }; void consume( const A& a ) { a.whoami(); } int main() { std::vector<B> a(10,B()); std::for_each( begin(a),end(a), [](const A& a) {consume(a); } ); return 0; }