using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Stack
{
    internal class StackBooksOfList
    {
        private NodeBook? firstBook = null;

        /// <summary>
        /// Возвращает элемент из стека
        /// </summary>
        /// <returns>Экземпляр книги</returns>
        public Book? pop()
        {
            if (firstBook == null)
            {
                return null;
            }
            else
            {
                NodeBook temp = firstBook;
                firstBook = firstBook.nextNodeBook;
                return temp.book;
            }
        }

        /// <summary>
        /// Добавление значения в стек
        /// </summary>
        /// <param name="newBook">Объект новой книги</param>
        public void push(Book newBook)
        {
            //Создание узла с книгой
            NodeBook newNode = new NodeBook();
            newNode.book = newBook;

            newNode.nextNodeBook = firstBook;
            firstBook = newNode;
        }

        
        public void printAll()
        {
            NodeBook temp = firstBook;
            while (temp != null)
            {
                Console.WriteLine(temp.book.name);
                temp = temp.nextNodeBook;
            }
        }


    }
}