Is the main part of the library. Organizes people and books in an efficient way. It has "LibExceptions" enum class and throws one of its values in case of error:

• bookNotFound
• bookNotAvailable
• bookTitleAlreadyExists
• bookISBNAlreadyExists
• bookAlreadyBought
• userAlreadyExists
• userNotFound

It has also the following functions:

• constuctor
• borrowBook
• returnBook
• requestBook
• buyBook
• addUser
• findBookByTitle
• findBookByISBN
• findUserByName

Paramter is a call-back function, to be called after every request after 50th request.

this function is to be called when a user called $userName borrows a book called $Booktitle.

this function is to be called when a user returns a book.

This function is to be called when user requests a book (throws BookException::hasBeenRequestedFromThisUser).

this function is to be called when a new Book is bought to be added to the repository.

adds new user to to librarry

returns the book with corresponding title from the repo.

returns the book with corresponding ISBN from the repo.

returns the user with corresponding name from the repo.

User Class implements a library user. It has the functionality. It has "UserException" enum class and throws one of its values in case of error:

• reachedMaxNumberOfBooks
• noSuchBook

It has the following functions:

• constructor
• borrowBook
• returnBook
• getName
• toString

creates a new user with User.name = name

add the borrowed book to the list of borrowed books of the user(a list of 10 books

remove the book from the list of borrowed books of the user

return name of the user

return user data as a string

Book class represent a book with a titile, author, ISBN and a potential borrower. It has "BookException" enum class and throws one of its values as exceptions:

• notAvailable
• notInRequest
• notBorrowed
• hasBeenRequestedFromThisUser

It has also "BookStatus" enum class which has the following potential values:

• available
• borrowed
• inRequest

It offers the following functions:

• constructor
• request
• isAvailable
• borrow
• returnBook
• buyFromWaitingList
• toString
• getUser
• getTitle
• getISBN
• getAuthor
• getStatus

creates a new book with given parameters.

increases request counter if user hasn't already requested and returns the new val.

return true if book status is available (already bought and not borrowed).

change book status to borrowed and saved the borrowing user.

change book status to available.

change book status from requested to availalbe

return book data as a string

shows the book borrower or throws exception if not borrowed

returns book title

returns book isbn

returns book author

return book status of data Type Book::Status