booklist *Book=new booklist; Book->next=NULL;
Book->bookname=m_bookname; Book->congshuname=m_congshuname; Book->datemonth=m_month; Book->dateyear=m_year; Book->ISBN=m_isbn; Book->price=m_price; Book->writer=m_writer; if(head_book==NULL)
head_book=Book;
else { { } else {
while(p->next) {
if(p->next->ISBN>m_isbn) {
Book->next=p->next;
if(p->ISBN>m_isbn)
Book->next=head_book; head_book=Book;