4 Topic 4. 15 points (Group, Implemented in C) Mini Library Create a system managing a mini library system. The users include borrower and librarian. Each user corresponds to a record (line) in a text file named “UserInfo.txt”. Each record consists of (User ID, First Name, Last Name, Account Name, Password, Role). The role ‘B’ represents borrower while ‘L’ represents librarian. Assume users’ information have been added to the file “UserInfo.txt” before the execution of the system.


 	UserInfo.txt	

1,First1 ,Last1, Acct1,1234,B 2,First2 ,Last2, Acct2, abcd,B 3,First3 ,Last3, Acct3, fffff,L

Every book corresponds to a record (line) in a text file named “mylibrary.txt”. Each record consists of 6 fields (Book ID, Title, Author, Possession, Check out Date, Due Date) separated by comma: Mylibrary.txt 1,Book1,Author1,Library,null,null 2,Book1,Author1,User1,2014-10-22,2014-11-21 3,Book2,Author2,User1,2014-10-23,2014-11-22 4,Book3,Author2,User2,2014-10-23,2014-11-22 5,Book4,Atuhor3,User2,2014-09-22,2014-10-22

l No comma “,”in title or author name. l This mini library keeps the record for each book in the library. Different books can share the book “Title”. But the “Book ID” for each book is unique. l One author may have multiple books. E.g. Both book2 and book3 are written by author1 l Possession field is “Library” means this book is kept in library, such as book #001. 
Otherwise, this book is checked out by the corresponding user. E.g. book #3 is checked out by User1. l A user is allowed to check out up to 3 books. l The “Checked out Date” field specifies the time of the latest checked out date. The loan period for each book is 30 days. “The Due Data” filed specifies the time the book should be returned. l This system asks the user to login by entering the correct account name and password.

If the user is a borrower, it provides a menu with following functionalities that the borrower can choose from at the top-level menu:

1. Enter “q” for book query by author sorted by book title. • 1) Ask for author • 2) List records of all books written by this author sorted by the book title. 5 • 3) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step 1))

2. Enter “s” for book status query by name • 1) Ask for book title. • 2) Examine if this book exists. If no, print a message “No such book!” and then go to 4). 
Otherwise, 3) • 3) List the possession status of these books. If the book is available, report it is in library; otherwise, report the available date to borrow it (the due date for this book). e.g. 1 Book1 In library 2 Book1 Available after 2014-11-21 • 4) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step 1))

3. Enter “u” to list books checked out by a given user • 1) Ask for current date and check if it is a legal date. If illegal, output “illegal input date” and go to step 4); otherwise, 2). • 2) List all books currently checked out by the given user. If the due date is passed, marked the record as “Over Due”. e.g. Assuming current date is 2014-12-01,for “User1” 2,Book1,Author1,User1,2014-10-22,2014-11-21 Over Due 3,Book2,Author2,User1,2014-10-23,2014-11-22 Over Due • 3) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step (1))

If the user is a librarian, it provides a menu with following functionalities that the librarian can choose from at the top-level menu:

1. Enter “a” to add a book into library • 1) Ask for title (read). • 2) Ask for author. • 3) Generate a book ID by adding one to the current largest book ID. • 4) Add the record of the new book into library with generated book ID, title, author, possession=”library”, checked out date=”null” and due date=”null”. After that, print message “book*** added successfully!” and go to step 5). • 5) Provide options “t” for “Try again” and “b” for “Back to main menu”. (If “Try again”, go to step 1))

2. Enter “d” to delete a book from library • 1) Ask for book ID. • 2) Examine if this book exists. If no, print a message “No such book!” and then go to 4). Otherwise, 3) • 3) Remove the book with the given book ID from the library and then go to 4). • 4) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step 1))

3. Enter “o” to check out a book • 1) Ask for user name. • 2) Count how many books this user has already checked out, only proceed the current checkout if less than 3 (go to 3)). Otherwise, go to 5) • 3) Ask for book Id, examine if this book exists. If no, print a message “No such book!” and then go to 5). Otherwise, 4) • 4) Update the possession, “check out date” and “due date” field of the corresponding book record. After that, print message “book*** checked out successfully!” and then go to 5). • 5) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step 1))

4. Enter “r” to return a book • 1) Ask for book ID. • 2) Examine if this book exists. If no, print a message “No such book!” and then go to 4). Otherwise, 3) • 3) Ask for current date and check if it is a legal date. If illegal, output “illegal input date” and go to step 7); otherwise, 4). • 4) Check if current date has passed “Due Date”. If no, go to step 6). Otherwise, 5) • 5) Output the current fine to this book. • 6) Assume user has already paid for fine if it exists. Update the possession and date fields of the corresponding record. After that, print message “book*** return successfully!” and then go to 7). • 7) Provide options “t” for “Try again” or “b” for “Back to main menu”. (If “Try again”, go to step 1))

5. Enter “x” to quit.