20 may 2020 doubly linked list deletion

#include <iostream>
using namespace std;
class DoublyLinkedList{
    public:
    int data;
    DoublyLinkedList* next;
    DoublyLinkedList* prev;
    DoublyLinkedList(int val)
    {
        this->data=val;
        this->next = NULL;
        this->prev = NULL;
    }
};
DoublyLinkedList *lastnode = NULL;
DoublyLinkedList* addatfront(DoublyLinkedList* head, int val)
{
    DoublyLinkedList* newnode = new DoublyLinkedList(val);
    if(head == NULL)
    {
        lastnode = newnode;
        return newnode;
    }
    newnode->next = head;
    head->prev = newnode;
    return newnode;

}
void print(DoublyLinkedList* head)
{
    DoublyLinkedList* curr = head;
    while(curr)
    {
        cout<<curr->data<<" ";
        curr= curr->next;
    }
}
DoublyLinkedList* removefront(DoublyLinkedList* head)
{
    if(head == NULL)
    {
        cout<<"Linked List is empty\n";
        return head;
    }
    if(head->next == NULL)
    {
        lastnode = NULL;
        delete head;
        return NULL;
    }
    head = head->next;
    delete head->prev;
    head->prev = NULL;
    return head;

}
DoublyLinkedList* removefromlast(DoublyLinkedList* head)
{
    if(head == NULL)
    {
        cout<<"Linked List is empty\n";
        return head;
    }
    if(head->next == NULL)
    {
        lastnode = NULL;
        delete head;
        return NULL;
    }

    lastnode = lastnode->prev;
    delete lastnode->next;
    lastnode->next= NULL;
     return head;
}
DoublyLinkedList* removegivenval(DoublyLinkedList* head, int val)
{
    if(head == NULL)
    {
        cout<<"Linked list is empty\n";
        return head;
    }
    DoublyLinkedList* curr = head;
    while(curr && curr->data != val)
    {
       curr = curr->next;
    }
    if(curr == NULL)
    {
        cout<<"Data not found\n";
        return head;
    }
    if(head == curr)
    {
        head = head->next;
    }
    if(lastnode == head)
    {
        lastnode = lastnode->prev;
    }
    if(curr->prev)
    curr->prev->next = curr->next;
    if(curr->next)
    curr->next->prev = curr->prev;
    delete curr;
    return head;


}

int main() {
    DoublyLinkedList* head = NULL;
   // head = removefromlast(head);
    head = addatfront(head,10);
    head = addatfront(head,20);
    head = addatfront(head,30);
    head = addatfront(head,40);
    head = addatfront(head,50);
    head = addatfront(head,60);
 // head = removefront(head);
    //head = removefromlast(head);
  //  head = removegivenval(head,20);
    head = removegivenval(head,60);
     
    

    print(head);

}