class book {
int book_number;
int student_number;
int date_publish;
int date_borrow;
int date_return;
char name[50];
string book_title, author;
public:
void get_data();
void show_data() const;
void show_tabular() const;
int return_book_number() const;
};
If you get more than one error you should start fixing the first one. Then recompile and repeat.
Because sometimes one error can cause many errors later in the code that are not real errors. Fixing the first error might make the later errors go away.
Does both the student class and the book class have a function named show_tabular()?