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Editorial Team
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Asked: 2026-05-28T04:15:03+00:00

std::map<Item*, item_quantity_t> _items; bool Inventory::hasItem(Item const& item) { return (_items.find(&item) != _items.end() ); };

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std::map<Item*, item_quantity_t> _items;

bool Inventory::hasItem(Item const& item) {

    return (_items.find(&item) != _items.end() );

};

This code won’t work, but changing the input type of “hasItem” to Item & item will work…
can someone explain why to me? I’ve seen that std::find takes a const reference, so passing it a const object should be ok, at least it’s what I understand

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1 Answer

  1. Editorial Team

    You’ve defined that the key type for your map is a pointer to a non-const Item, Item*. The find method expects a (const reference to a) value of the key type, so it requires a pointer to non-const.

    When you expand the templates, the parameter type of find is Item* const&.

    You can either change your hasItem to take a non-const reference Item&, or you can change your key type to be a pointer to a const Item Item const*.

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