std::list<T,Allocator>::emplace

template< class... Args >
iterator emplace( const_iterator pos, Args&&... args );

#include <iostream>
#include <string>
#include <list>
 
struct A
{
    std::string s;
 
    A(std::string str) : s(std::move(str)) { std::cout << " constructed\n"; }
 
    A(const A& o) : s(o.s) { std::cout << " copy constructed\n"; }
 
    A(A&& o) : s(std::move(o.s)) { std::cout << " move constructed\n"; }
 
    A& operator=(const A& other)
    {
        s = other.s;
        std::cout << " copy assigned\n";
        return *this;
    }
 
    A& operator=(A&& other)
    {
        s = std::move(other.s);
        std::cout << " move assigned\n";
        return *this;
    }
};
 
int main()
{
    std::list<A> container;
 
    std::cout << "construct 2 times A:\n";
    A two{"two"};
    A three{"three"};
 
    std::cout << "emplace:\n";
    container.emplace(container.end(), "one");
 
    std::cout << "emplace with A&:\n";
    container.emplace(container.end(), two);
 
    std::cout << "emplace with A&&:\n";
    container.emplace(container.end(), std::move(three));
 
    std::cout << "content:\n";
    for (const auto& obj : container)
        std::cout << ' ' << obj.s;
    std::cout << '\n';
}