cppSTLInsertEmplacePush_backDifference

#include<iostream>
#include <vector>
#include <algorithm>

class Item
{
public:
    Item() { std::cout << "Item default constructed " << this << '\n'; }
    Item(const Item& it) { std::cout << "Item copy constructed " << this << " from " << &it << '\n'; }
    Item(Item&& it) { std::cout << "Item move constructed " << this << " from " << &it << '\n'; }
    Item& operator=(const Item& it) { std::cout << "Item copy assigned " << this << " from " << &it << '\n'; return *this; }
    Item& operator=(Item&& it) { std::cout << "Item move assigned " << this << " from " << &it << '\n'; return *this; }
    ~Item() { std::cout << "Item destructed " << this << '\n'; }
    friend std::ostream& operator<<(std::ostream& out, const Item& item)
    {
        return out << "Item # " << &item;
    }
};



int main()
{
    Item it;

    std::vector<Item> items;
    std::cout << "Pre reserve\n";
    items.reserve(3);
    std::cout << "Post reserve\n";
    //items.emplace_back(Item{});
    items.emplace(items.end());
    items.emplace(items.end());
    //items.insert(items.begin(), it);
    //items.insert(items.begin(), Item{});
    //items.emplace(items.begin());

    std::copy(items.begin(), items.end(), std::ostream_iterator<Item>(std::cout, "\n"));
}