Double Linked List

#include <iostream>
using namespace std;

class node {
      public :
             int data;
             node *nextnode;
             node *prevnode;
             
             node() {
                  data = 0;
                  nextnode = NULL;
                  prevnode = NULL;
                  }
             };
             
class list {
      private :
             node *head;
             node *tail;
             
      public : 
             list() {
                  head = NULL;
                  tail = NULL;
                  }
                  
             bool empty()
             {
                 tail = NULL;
                 return (head==NULL);
             }
             
             void push_front()
             {
                 node *ptr;
                 ptr = new node;
                 cout << "Enter value to insert : \n";
                 int v;
                 cin >> v;
                 ptr->data = v;
                 ptr->nextnode = NULL;
                 ptr->prevnode = NULL;
                 if (head!=NULL)
                 {
                     ptr->nextnode = head;
                     ptr->prevnode = NULL;
                 }
                 head = ptr;
                 cout << "\n \t" << ptr->data << "\t Pushed Successfully \n";
             }
             
             void push_back ()
             {
                node *ptr;
                ptr = new node;
                node *last;
                last = head;
                cout << "Enter value to insert : \n";
                int v;
                cin >> v;
                ptr->nextnode = NULL;
                if (empty())
                {
                    ptr->prevnode = NULL;
                    head = ptr;   
                }
                while (last!=NULL)
                {
                    last = last->nextnode;
                    //last->nextnode = ptr; // remove if removing comment tag on the below comment tagged lines
                    //ptr->prevnode = last; // remove if removing comment tag on the below comment tagged lines
                }
                last->nextnode = ptr;
                ptr->prevnode = last;
                cout << "\n \t" << ptr->data << "\t Pushed Successfully \n";
             }
                 
             
             void pop_front()
             {
                 node *temp;
                 if (empty())
                 {
                     cout << "List Is Empty \n :";
                 }
                 temp = head;
                 head = head->nextnode;
                 cout << "\t" << temp->data << " \t Popped From Front Successfully \n";
                 delete temp;
                 }
                 
             /*void pop_back()
             {
                 node *temp;
                 if (empty())
                 {
                     cout << "List Is Empty \n";
                 }
                 temp = head;
                 while (temp!=NULL)
                 {
                     temp = temp->nextnode;
                     tail = temp;
                 }
                 --temp;
                 cout << "\t";
                 delete temp;
             }*/
             
             /*void append()
             {
                  code here
             }*/
             
             /*void deletenode()
             {
                  code here
             }*/
                              
             void count()
             {
                  node *count;
                  int length;
                  count = head;
                  while (count!=NULL)
                  {
                      length++;
                      count = count->nextnode;
                  }
                  cout << "Number Of Nodes In The List Is : " << length << endl;
                  }
                  
             void display()
             {
                  node *dp;
                  dp = head;
                  while (dp!=NULL)
                  {
                      cout << dp->data << "<====>";
                      dp = dp->nextnode;
                  }
                  cout << "NULL \n";
                  }
             };
             
             int main() {
                 list l;
                 int c;
                 while (1)
                 {
                     cout << "\n \t MENU : \n 1) PUSH : \n 2) POP : \n 3) DISPLAY : \n 4) SIZE : \n 5) EXIT : \n 6) PB :";
                     cout << "\n \n Enter desired action : \n";
                     cin >> c;
                     switch(c)
                     {
                              case 1 :
                                   l.push_front();
                                   break;
                                   
                              case 2 :
                                   l.pop_front();
                                   break;
                                   
                              case 3 :
                                   l.display();
                                   break;
                                   
                              case 4 :
                                   l.count();
                                   break;
                                   
                              case 6 :
                                   l.push_back();
                                   break;
                                   
                              case 5 :
                                   return 0;
                                   break;
                                   
                              default :
                                      cout << "Enter valid choice : \n";
                     }
                 }
                 return 0;
             }