Formal description Technology and book circulation system.

1. Under what circumstances should formal description techniques be used? What guidelines should be followed when using formal specification techniques?

when people understand the specification described in natural language, it is easy to produce two semantics. In order to overcome the shortcomings of non-formal methods, people put mathematics into software development engineering, and created a formal description technology based on mathematics.

The criterion of applying formal method: The expression method of releasing should be chosen; it should be formalized, but not overly formalized; there should be a formal approach to consulting at any time, and there should be a formalization of the methodology; you should not abandon the traditional methods of development; You should not blindly rely on formal methods. ; should be tested, tested and re-tested;

2, book circulation System.

Each book has a barcode, and everyone has a card with a barcode. But when a borrower wants to borrow a book, the librarian scans the barcode on the book and the barcode of the borrower's card, then enters C on the computer terminal, and when the book is returned, the librarian scans again and enters R. The librarian can add some books to the (+) book collection, or they can delete (-) them. The borrower can find all the books of an author (enter "A=" and the author's name) on the terminal, or all books with the specified title (enter "t=" and title), or all books that fall within a specific subject range (enter "s=" plus the subject range). Finally, if the borrower wants to borrow the book has been borrowed by others, the librarian will give the book an appointment, so that the book return to the book to the reservation of the borrower (enter "H=" plus ISBN).

Formal description Technology and book circulation system.