#include <bits/stdc++.h>

using namespace std;

#define null NULL

struct Node{

int data;

Node *link;

};

Node *head = null;

void insertBeg(int d){

Node *ptr = new Node();

ptr->data = d;

ptr->link = head;

head = ptr;

}

void insertend(int d){

Node *ptr = new Node();

ptr->data=d;

ptr->link=null;

if(head==null){

head = ptr;

}

else{

Node *temp = head;

while(temp!=null){

temp=temp->link;

}

temp->link = ptr;

}

}

void deleteBeg(){

if(head ==null){

cout<<"Empty list";

}

else{

Node *ptr = head;

head = ptr->link;

free(ptr);//del the node from memory

}

}

void deleteend(){

Node *ptr = head;

Node *prev = null;

if(head ==null){

cout<<"Empty list";

}

else if(head->link==null){

ptr=head;

head = null;

free(ptr);

}

else{

while(ptr!=null){

prev = ptr;

ptr = ptr-> link;

}

prev->link = null;

free(ptr);

}

}

int middleelement(){

Node *slow,*fast;

slow = head;

fast = head;

if(head==null){

cout<<"empty list";

}

else{

while(fast->link!=null || fast==null){

fast = fast->link->link;

slow = slow->link;

}

return slow->data;

}

}

void reverselist(){

Node *prev,*curr,*forw;

prev=null;

curr = head;

while(curr!=null){

forw = curr->link;

curr->link = prev;

prev=curr;

curr = forw;

}

head = prev;

}

void delnode(Node *ptr){

Node *temp;

temp=ptr->link;

ptr->data = temp->data;

ptr->link = temp->link;

free(temp);

}

int main()

{

ios_base::sync_with_stdio(false);

cin.tie(NULL);

Node*ptr = new Node();

ptr -> data =2;

ptr->link = null;

head = ptr;

}