bilist

#include <stdio.h>


template <typename T>
class bilst
{
  struct node {
    node *next;
    node *prev;
    T val;
  };
  node* nil;
  
  void insert(T e) 
  {
    node* n = new node();
    n->val = e;
    n->next = nil->next;

    nil->next->prev = n;
    nil->next = n;
    n->prev = nil;
  }
  void del(T e)
  {
    node* n = new node();
    n->val = e;
    n->prev->next = n->next;
    n->next->prev = n->prev;
  }
  bool search(T e) {
    node x = nil->next;
    while (x != nil) {
      if (x->val == e.val) {
	return true;
      }
      x = x->next;
    }
    return false;
  }
};