I know exactly similar questions have been already proposed, but those questions focus on how to create a new template class. My question is about how to use existing template classes such as std::list, std::map, which makes it even more confusing for me.
I am now creating a template class for LRU Caching. I do it like this:
template <typename KT, typename VT>
class LRUCache{
private:
struct Node{
KT key;
VT value;
Node(KT k, VT v) : key(k), value(v) {}
};
public:
LRUCache(int c) : capacity(c) {}
VT get(KT key) { ... }
void set(KT key, VT value) { ... }
private:
int capacity;
std::list<Node> cacheList;
std::unordered_map<KT, std::list<Node>::iterator> cacheMap;
};
I got an error type/value mismatch at argument 2 in template parameter list for ‘template<class _Key, class _Tp, class _Hash, class _Pred, class _Alloc> class std::unordered_map’. It seems confusing for me to understand this. One of the previous proposed problems mentions that std::list has more than one class parameters in its template, and now std::unordered_map seems to have 5. What should I do know?
