Error with peek() function of a Stack class in c++ - c++

Question

I am trying to implement the peek() function of a Stack class and have this issue where I cannot return the top object of the stack, but instead get an error. I have tried removing the & to the peek function and tried to set it to a const, but I still get errors. Would the issue be outside of this function? as I am not sure what else I can try to solve this problem.
Error:
LStack.h:55:28: error: cannot bind non-const lvalue reference of type ‘int&’
to
an rvalue of type ‘int’
return data.get_current();
LStack.h
#include "LinkedList.h"
#include <cstdlib>
#include <iostream>
template <typename T>
class LStack
{
public:
//mutator member functions
LStack(){}
~LStack(){}
void push(const T& obj) //insert obj at the top of the stack
{
data.add_to_head(obj);
numofstacks++;
}
T pop() //remove and return the top object from the stack, error if stack is empty
{
if (is_empty()){
std::cout << "Stack is empty";
}
else{
data.remove_from_head();
numofstacks--;
return data.get_current();
}
}
bool is_empty() const //return a boolean indicating whether the stack is empty
{
return (size() == 0);
}
//query member functions
int size() const //return the number of objects in the stack
{
return numofstacks;
}
//return a reference to the object at the top of the stack, NULL if the stack is empty, (also refered to as top())
T& peek()
{
if (is_empty()){
std::cout << "Stack is empty";
}
else{
//return top of the stack object
return data.get_current();
}
}
private:
LinkedList<T> data;
int used;
int numofstacks;
};
LinkedList.h
#include "Node.h"
#include <cstdlib>
#include <iostream>
template <typename T>
class LinkedList
{
public:
LinkedList() //constructor
{
head = NULL;
tail = NULL;
list_length=0;
}
~LinkedList()//destructor since we're creating the linked list on the heap
{
while (head != NULL)
{
remove_from_head();
}
tail = NULL;//not sure if in or out of while loop
}
LinkedList(T& item)
{
head = new Node<T>();
head->set_data(item);
tail = head;
list_length = 1;
}
void add_to_head(T item)
{
if (list_length == 0){ //if list is empty
head = new Node<T>();
head->set_data(item);
tail = head;
list_length = 1;
}
else //Else if list is not empty.. Insert node at the head
{
Node<T>* head_insert = new Node<T>();
head_insert->set_data(item);
head->set_prev(head_insert);
head_insert->set_next(head);
head = head_insert;
list_length++;
head_insert = NULL;
}
}
void add_to_tail(T item)
{
if (list_length == 0){
head = new Node<T>();
head->set_data(item);
tail = head;
list_length = 1;
}
else //insert node at tail
{
Node<T>* tail_insert = new Node<T>();
tail_insert->set_data(item);
tail->set_next(tail_insert);
tail_insert->set_prev(tail);
tail = tail_insert;
list_length++;
tail_insert = NULL;
}
}
void remove_from_head()
{
if (list_length == 0){
return;
}
else if (list_length == 1){
delete head;
head = NULL;
tail = NULL;
list_length--;
return;
}
else
{
Node<T>* temp_head = head;
head = temp_head->get_next();
delete temp_head;
list_length--;
temp_head = NULL;
}
}
void remove_from_tail()
{
if (list_length == 0){
return;
}
else if (list_length == 1)
{
delete head;
head = NULL;
tail = NULL;
list_length--;
return;
}
else
{
Node<T>* temp_tail = tail;
tail = temp_tail->get_prev();
delete temp_tail;
list_length--;
temp_tail = NULL;
}
}
std::size_t size()
{
return list_length;
}
T get_current() // RESULTS IN SEG ERROR
{
return current->get_data();
}
void forward()
{
current = current->get_next();
}
void back()
{
current = current->get_prev();
}
void move_to_head()
{
current = head;
}
void move_to_tail()
{
current = tail;
}
private: //private members
Node<T>* head; //point to start of list
Node<T>* tail; //point to end of list
Node<T>* current; //optional - used to refer to a node in our list
std::size_t list_length;
};
Would the issue be outside of this function? as I am not sure what else I can try to solve this problem.