#include <iostream>
#include <memory>
#include <cassert>

class foo {
public:
    void print() {
        std::cout << "foo::print" << std::endl;
    }
};

class bar {
public:
    std::unique_ptr<foo> ptr;
};

int main()
{
    std::unique_ptr<foo> a = std::make_unique<foo>();
    a->print();

    assert(a);
    bar new_owner;
    new_owner.ptr = std::move(a);
    assert(!a);
    new_owner.ptr->print();


    return 0;
}