Can this code be modified for hash usage

[funprogrammer]

Hi Fellow programmers,
I was implementing hash map using ordered map. I was reading online about std::hash function and I did not know how to use it here. Can someone help?

bool LinkedList::checkDuplicates(){
   Node *prev, *leaf;
   std::unordered_map<int, Node*> hash;
   prev = head;
   leaf = head->next;
   while(leaf){
      auto elem = hash.find(leaf->value);
      if(elem == hash.end()){
         hash.insert(std::pair<int, Node*>(leaf->value, leaf));
         prev = leaf;
         leaf=leaf->next;
      }
      else{
         cout << "Duplicate element found" << endl;
         prev->next = leaf->next;
         delete leaf;
         return true;
      }
   }
}

[LB]

std::unordered_map implements a hash map already and uses std::hash.

http://www.cplusplus.com/reference/unordered_map/unordered_map/
http://en.cppreference.com/w/cpp/container/unordered_map

http://www.cplusplus.com/reference/functional/hash/
http://en.cppreference.com/w/cpp/utility/hash