#include <iostream>

struct A
{
    A()
    {
        std::cout << "A::A()" << std::endl;
    }
    A(A const &other)
    {
        std::cout << "A::A(A const &other)" << std::endl;
    }
    ~A()
    {
        std::cout << "A::~A" << std::endl;
    }
};

struct Keeper
{
    A getByValue()
    {
        return a_;
    }

    A &getByRef()
    {
        return a_;
    }

    A a_;
};

int main()
{
    Keeper k;
    {
        A &local = k.getByRef();
        std::cout << "get by ref" << std::endl;
    }
    {
        A const &local = k.getByValue();
        std::cout << "get by value to ref" << std::endl;
    }

    //A &local = k.getByValue();
    //error: invalid initialization of non-const reference of type ‘A&’ from an rvalue of type ‘A’
    {
        A local = k.getByValue();
        std::cout << "get by value to value" << std::endl;
    }

    std::cout << "program end" << std::endl;

    return 0;
}