doubly link list in c++

[srad]

Hi..Im writting a doubly link list in c++,compiled with Turbo c++, but my Add_at_first method seems not working,i couldnt find any problem in the code...
here is the code :

#include <iostream.h>
class node
{  friend class linklist;
  public :    int num;
    node *next;
    node *prev;
};
class linklist{
    public :
    void add_at_first();
 
    private :
    node *first;
    node *last;
};
//*******Add At First**
void linklist :: add_at_first()
{  
   node *temp;
   temp = new node();
   temp ->prev=temp ->next=NULL;
   cout <<"Please Enter A Number :"<< endl;
   cin >> temp -> num;
 
   if(first ==last==NULL)// if the list is empty
   {
      first = last=temp;
   }
   else
   {  
      first -> prev =temp;
      temp -> next = first;
      first = temp;
   }
}

waitting for ur guidance, Thanksss..

[Ganon11]

Well, in a doubly-linked list, you probably shouldn't need last - to find the last node, you code just use first->prev.

Next, if the list is not empty, you are adjusting first and temp - but you will need to change last (or, if you follow the first example, first->prev) to point forward to temp.

[Banfa]

Well, in a doubly-linked list, you probably shouldn't need last - to find the last node, you code just use first->prev.

Only true if your list is circular as well as doubly linked.

[Ganon11]

Only true if your list is circular as well as doubly linked.

...right. I keep forgetting to distinguish the two.

[Banfa]

...right. I keep forgetting to distinguish the two.

Ah, not all four legged animals are cows :D