试图将函子放置在std :: unordered_map中

Question

I got my inventory

std::unordered_map<std::reference_wrapper<Item>, int, ItemHasher> items;

ItemHasher is

struct ItemHasher
{
    std::size_t operator()(const std::reference_wrapper<Item>& item) const
    {
        return item.get().getHash();
    }
};

How to emplace item in my map? I tried

items.try_emplace(item, 1, /*Different variants*/);

But it isn't working as it should.

Answer 1

unordered_map stores the hasher it uses already. It makes scant sense to pass another one to try_emplace .

items.try_emplace(item, 1);