#pragma once
#include <iostream>

using namespace std;

struct Node
{
	int data;
	Node* next;

	Node(int data, Node* next) {
		this->data = data;
		this->next = next;
	}

	friend 	ostream & operator<< (ostream & out, const Node & x);
};


class Error { 
};


class List {
private:
	Node* first;
	Node* last;
	Error err;
public:
	List() ;
	~List();
	bool isEmpty() const;
	void push_back(int x);
	int operator[] (int i)const;
	List& operator=(const List& other);
	
	friend ostream & operator << (ostream & out, const List & y);

};