Traversing through Doubly linked list (DLL)

//creating and displaying dll
#include<stdio.h>
#include<iostream.h>
#include<conio.h>
template<class T>
class node
{
 node<T> *llink;
 T data;
 node<T> *rlink;
 friend class dll<T>;
};
template <class T>
class dll
{
 private:
        node<T> *l,*r;
 public:
        dll();
       ~dll();
        int isempty();
        void display();
        int length();
        void insert(int i, T x);
        int del(int i);
        T find(int i);
node<T>* search(T x);
void erase();
void append(node<T>*k);
void create();
};
template<class T>
dll<T>::dll()
{
 l=r=NULL;
}
template<class T>
int dll<T>::isempty()
{
 return(l==NULL);
}
template<class T>
void dll<T>::display()
{

 node<T> *p;
 if(isempty())
 {
  cout<<"DLL is empty\n";
 }
 else
 {
   cout<<"DLL is as follows\n";
   for(p=l;p!=NULL;p=p->rlink)
// displaying from last to first
//// for(p=l;p!=NULL;p=p->link)
     cout<<p->llink<<"\t"<<p->data<<"\t"<<p->rlink<<"\n";
 }
}
//length()
template<class T>
int dll<T>::length()
{
 int ctr=0;
 node<T> *p;
 p=l;
 while(p!=NULL)
 {
  ctr++;
  p=p->rlink;
 }
 return(ctr);
}
//find()

template<class T>
T dll<T>::find(int i)
{
 node<T> *p;
 if(i<1||i>length())
  return(-1);
 p=l;
 for(int j=1;j<=i-1;j++)
  p=p->rlink;
 return(p->data);
}
//search()
template<class T>
node<T>* dll<T>::search(T x)
{
 node<T> *p;
 p=l;
 while(p!=NULL)
 {
 if(p->data==x)
  return(p);
 }
 return(NULL);
}
//apend()
template<class T>
void dll<T>::append(node<T>* k)
{
 node<T> *last;
 k->rlink=NULL;
 if(isempty())
   l=r=k;
 else
 {
   //last=r;
   last=l;
   while(last->rlink!=NULL)
   {
    last=last->rlink;
   }
   last->rlink=k;
   r=last;
  }
}
//create()
template<class T>
void dll<T>::create()
{
  T x;
  node<T> *k;
  l=r=NULL;
  cout<<"enter values terminated by -1 or !\n";
  cin>>x;
  while(x!=-1&&x!='!')
  {
   k=new node<T>;
   k->data=x;
   append(k);
   cin>>x;
   r=r->rlink;
  }
 }//create()
   //insert()

template<class T>
dll<T>::~dll()
{

}

main()
{
 dll<int>a;
 node<int>*p;
 int ch,i,x;
 clrscr();
 a.create();
 a.display();
getch();
return(0);
}//main()

Doubly Linked List Operations

Types of Linked list

Single Linked List

Doubly Linked List

Circular Linked List 

Programs on Doubly Linked List

Node class structures

Some terminology of Doubly Linked List programs