#include <memory>
#include <iostream>

struct Foo
{
    ~Foo() { std::cout << "Foo\n"; }
};

struct Bar : public Foo
{
    ~Bar() { std::cout << "Bar\n"; }
};

int main()
{
    {
        std::cout << "shared_ptr:\n";
        std::shared_ptr<Foo> f(new Bar()); // prints Bar Foo
    }

    {
        std::cout << "unique_ptr:\n";
        std::unique_ptr<Foo> f(new Bar()); // prints Foo
    }
}