cannot access private member declared in class: queue class template - c++

Question

I have to write code to implement template queue
I get this error : cannot access private member declared in class
at this line
front=front->next;
this is the header file of my code where I get the error:
#include <iostream>
#pragma once
using namespace std;
typedef int Error_code;
#define SUCCESS 0
#define OVERFLOW -1
#define UNDERFLOW -2
template <class T>
class Node{
T item;
Node * next;
Node(){item=0; next=NULL;}
Node(T n){item=n; next=NULL:}
};
template <class T>
class queue
{
protected:
Node<T>* front; // pointer to front of Queue
Node<T> * rear; // pointer to rear of Queue
int count; // current number of items in Queue
public:
queue();
~queue();
bool isempty(){
//return count == 0;
if(front==NULL)
return true;
else
return false;
};
bool isfull(){return false;};
Error_code serve(){
Error_code outcome = SUCCESS;
Node<T> *p;
if(isempty()){
cout<<"empty queue";
outcome=UNDERFLOW;
}
else{
p=front;
front=front->next;
delete p;
count--;
}
return outcome;
} ;
Error_code retrieve(T &item){
Error_code outcome SUCCESS;
if(isempty())
{ // front node is empty, queue is empty
//return false;
cout<<"empty queue";
outcome=UNDERFLOW;
}
return outcome;
};
Error_code append(T item){
Node<T> * n ;
n= new Node; // create node
n->item = item; // set node pointers
n->next = NULL;
if (isempty())
{
rear=front = n;
}
else
{
rear->next = n; // else place at rear
rear = n; // have rear point to new node
}
count++;
return SUCCESS;
};
};

Answer 1

front is a pointer to Node, but next is a private member in Node
template <class T>
class Node{
T item; // since you didn't specify access level
Node * next; // explicitly the access is private by default
Node(){item=0; next=NULL;}
Node(T n){item=n; next=NULL:}
};
so you cannot use it in queue class:
front=front->next; // error
change it to be public or redesign the program