[Solved] why I cannot properly overload an operator with a templated param?

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C++

overloading

templates

g++

, +

How do we properly create an overloaded operator specifically this "<<" and also with a templated parameter?

I do had an implementation of it but the problem was and for some reason the output was an address/reference of it, and my custom overloaded operator did not work?

And I stumbled upon this syntax where I have this second parameter of a declaration and which had an empty type-param. Why does the compiler did not complaint? maybe because I initialized this template see @ "What Have you Tried" and it can still be ran but for me its like a bug cause it did not work as I intended for?

std::ostream& operator<<(std::ostream& out, const HashNode</*empty*/>& node) {
    return out << "[ " << "key: " << node.getKey() << ", " << "val: " << node.getValue() << " ]";
}

What I have tried:

//REM: HashNode.h
template<typename K = int, typename V = std::string>
class HashNode { ... };
template<typename K = int, typename V = std::string>
std::ostream& operator<<(std::ostream& out, const HashNode<K, V>& node) {
    out << "[ " << "key: " << node.getKey() << ", " << "val: " << node.getValue() << " ]";
    return out;
}

//REM: then we stream it out
//HashNode<float, int> hNodeF = new HashNode<float, int>();
HashNode<>* hNode = new HashNode<>();
hNode->setKey(777);
hNode->setValue("lucky?");
std::cout << hNode << std::endl; // why only an address or reference show up, why does my overload operator not working?
delete hNode;