C++

I have failed to call the insert and display. I am recycling code but cannot figure out how to insert a node at the beginning and display it. Please help

#ifndef LINKEDLIST_H_INCLUDED #define LINKEDLIST_H_INCLUDED #include #include #include

using namespace std; template struct Node { T data; Node *Next, *Previous; };

template class Linkedlist { private: Node *First; Node *Last; Node *TempPrevious; Node *TempNext; Node *P; int length;

public:

Linkedlist() { First = NULL; Last = NULL; length = 0; }

void insertfirst(const T & data) { P = new Node; length++;

P->Previous = NULL; P->data = data; P->Next = First; P = First;

if (length == 1) P = Last;

if (length > 1) { P = P->Next; P -> Previous = First; } }

void display() { if( length > 0) { cout << " List has " << length << " elements "; P = First;

while(P!= NULL) { if ( P->Next != NULL) { cout << P -> data << " at Memory Address " << P << " Pointing to " << P->Next << " "; }

else { cout << P -> data << " at Memory Address " << P << " Pointing to " << "Null "<< " "; } P = P -> Next; } } else cout << " LIST is EMPTY!";

}

};

#endif // LINKEDLIST_H_INCLUDED