You will be writing a Library simulator. It will have three classes: Book, Patron and Library. To make things a little simpler for you, I am supplying you with the three .hpp files. You will write the three implementation files. You should not alter the provided .hpp files.
A couple of notes:
- The vector::erase() function lets you delete an element of a vector, shifting over all the elements after it.
- You’ll see in Book.hpp a line that says “class Patron;”. That is a forward declaration. It doesn’t say anything about the definition of the Paton class, but it promises the compiler that there will be a type named Patron. The reason we don’t just say “#include Patron.hpp” is that both Book and Patron need to know about each other, but they can’t both #include the other because that would create a cyclic dependency.
Here are the .hpp files: Book.hpp, Patron.hpp and Library.hpp
Here are descriptions of the three classes:
Book:
- idCode – a unique identifier for a Book (think library bar code, not ISBN)
- title – cannot be assumed to be unique
- author – the idCode, title and author don’t need set methods, since they will never change after the object has been created, therefore these fields can be initialized directly within the constructor
- location – a Book can be either on the shelf, on the hold shelf, or checked out
- checkedOutBy – pointer to the Patron who has it checked out (if any)
- requestedBy – pointer to the Patron who has requested it (if any); a Book can only be requested by one Patron at a time
- dateCheckedOut – when a book is checked out, this will be set to the currentDate of the Library
- CHECK_OUT_LENGTH – constant that gives how long a Book can be checked out for
- constructor – takes an idCode, title and author; checkedOutBy and requestedBy should be initialized to NULL; a new Book should be on the shelf
- some get and set methods
Patron:
- idNum – a unique identifier for a Patron
- name – cannot be assumed to be unique
- checkedOutBooks – a vector of pointers to Books that Patron currently has checkedOut
- fineAmount – how much the Patron owes the Library in late fines (measured in dollars); this is allowed to go negative
- a constructor that takes an idNum and name and initializes fineAmount to zero
- some get and set methods
- addBook – adds the specified Book to checkedOutBooks
- removeBook – removes the specified Book from checkedOutBooks
- amendFine – a positive argument increases the fineAmount, a negative one decreases it
Library:
- holdings – a vector of pointers to Books in the Library
- members – a vector of pointers to Patrons in the Library
- currentDate – stores the current date represented as an integer number of “days” since the Library object was created
- a constructor that initializes the currentDate to zero
- addBook – adds the parameter to holdings
- addPatron – adds the parameter to members
- getBook – returns a pointer to the Book corresponding to the ID parameter, or NULL if no such Book is in the holdings
- getPatron – returns a pointer to the Patron corresponding to the ID parameter, or NULL if no such Patron is a member
- checkOutBook
- if the specified Book is not in the Library, return “book not found”
○ if the specified Patron is not in the Library, return “patron not found”
○ if the specified Book is already checked out, return “book already checked out”
○ if the specified Book is on hold by another Patron, return “book on hold by other patron”
○ otherwise update the Book’s checkedOutBy, dateCheckedOut and Location; if the Book was on hold for this Patron, update requestedBy; update the Patron’s checkedOutBooks; return “check out successful”
- returnBook
- if the specified Book is not in the Library, return “book not found”
○ if the Book is not checked out, return “book already in library”
○ update the Patron’s checkedOutBooks; update the Book’s location depending on whether another Patron has requested it; update the
Book’s checkedOutBy; return “return successful”
- requestBook
- if the specified Book is not in the Library, return “book not found”
○ if the specified Patron is not in the Library, return “patron not found”
○ if the specified Book is already requested, return “book already on hold”
○ update the Book’s requestedBy; if the Book is on the shelf, update its location to on hold; return “request successful”
- payFine
- takes as a parameter the amount that is being paid (not the negative of that amount)
○ if the specified Patron is not in the Library, return “patron not found”
○ use amendFine to update the Patron’s fine; return “payment successful”
- incrementCurrentDate
- increment current date; increase each Patron’s fines by 10 cents for each overdue Book they have checked out (using amendFine)
○ If a book is checked out on day 0, then on day 1, the patron has had it for 1 day. On day 21, the patron has had it for 21 days, so it is still not overdue. On day 22, the book is overdue and fines will be charged.
- be careful – a Book can be on request without its location being the hold shelf (if another Patron has it checked out);
One limited example of how your classes might be used is:
Book b1(“123”, “War and Peace”, “Tolstoy”);
Book b2(“234”, “Moby Dick”, “Melville”);
Book b3(“345”, “Phantom Tollbooth”, “Juster”);
Patron p1(“abc”, “Felicity”);
Patron p2(“bcd”, “Waldo”);
Library lib; lib.addBook(&b1); lib.addBook(&b2); lib.addBook(&b3); lib.addPatron(&p1); lib.addPatron(&p2); lib.checkOutBook(“bcd”, “234”); for (int i=0; i<7; i++) lib.incrementCurrentDate(); lib.checkOutBook(“bcd”, “123”); lib.checkOutBook(“abc”, “345”); for (int i=0; i<24; i++) lib.incrementCurrentDate(); lib.payFine(“bcd”, 0.4); double p1Fine = p1.getFineAmount(); double p2Fine = p2.getFineAmount();
This example obviously doesn’t include all of the functions described above. You are responsible for testing all of the required functions to make sure they operate as specified.
