ss Article implements LibraryItemInterface{Р private String m_title; //论文名Р private String m_author; //论文作者Р private int m_start_page;Р private int m_end_page;Р public Article(String p_author, String p_title,int p_start_page,int p_end_page){Р m_title=p_title; Р m_author= p_author;Р m_end_page=p_end_page;Р }Р public int getNumberOfPages(){Р return m_end_page - m_start_page;Р }Р public void accept(LibraryVisitor Visitor){Р (4) ;Р }Р}Рclass Book implements LibraryItemInterface{Р private String m_title; //书名Р private String m_author; //书作者Р private int m_pages; //页教Р public Book(String p_author, String p_title,int p_ pages){Р m_title= p_title;Р m_author= p_author;Р m_pages= p_pages;Р }Р public int getNumberOfPages(){Р return m_pages; Р }Р public void accept(LibraryVisitor visitor){Р (5) ;Р }Р}