Lab4: Inheritance and abstract base classes

Objective: To be familiar with ordered STL list, inheritance and
abstract base classes.
Description: In this assignment, you will build an interactive program
for a video store that sells DVD and books. When the program starts,
it loads inventory from an external file inventory.txt. Each line in
the inventory.txt file contains the information of one DVD/Book in one
of the following formats:
 |Movie|barcode|movie name|director(s) of the movie|movie
price|number of copies currently in stock|number of DVD's to
be ordered|
 |Book|barcode|title of the book|author(s) of the book|publish
date|book price|number of copies currently in stock|number of
books to be ordered|
Each item in the line is separated by “|”.
The inventory should be maintained in alphabetical order by barcode
instead of title.
The program should provide the following commands:
'M'--Inquire about a specific movie by title and display inventory
information for the specified movie. The user should be asked to
input a movie title and your program should print out all
information related to that movie.
'B'--Inquire about a specific book by author and display inventory
information for the specified book. The user should be asked to
input (partial) name of an author and your program should print out
all information of the book written by that author. You may need to
use code similar to the following to allow the user to input only
portions of the author’s name.
string str1( "Alpha Beta Gamma Delta" );
string::size_type loc = str1.find( "Omega", 0 );
if( loc != string::npos )
cout << "Found Omega at " << loc << endl;
else
cout << "Didn't find Omega" << endl;
'R'--Return a movie/book to the inventory. The user should be asked
to input the bar code. If the movie/book is in the inventory, the
number of copies of the item should be increased by 1 if the number
of copies to be ordered is 0, or decrease the number of copies to
be ordered by 1 if it is greater than 0.
'L'-- List the entire inventory in alphabetical order by barcode'C'--Check out a movie/book. The user should be asked to input a
barcode. If the item is in the inventory and the number of copies
of the item is 0, your program should decrease the number of
copies on hand by one. If the item is in the inventory but there
are no copies available, the number of copies to be ordered should
be increased by 1. If the item is not in the inventory, an error
message should be printed.
'Q'-- Quit the program. No need to save the inventory information.
Design: This assignment contains several classes: StoreItem, Movie,
and Book.
 StoreItem: This is the base class of the classes Movie and Book.
A store item can have barcode, price for the item, number of
copies of the item in the inventory and number of copies to be
ordered. The declaration of StoreItem class is provided by the
instructor.
 Movie: Represents DVD information. It is a derived class of
StoreItem.
 Book: Represents Book information. It is a derived class of
StoreItem.
The file ola4.cpp should provide the program’s user interface: read
user’s input and execute appropriate commands. The inventory must
be represented as a list of StoreItem pointers (i.e. list<StoreItem
*) in order to explore the benefits of polymorphism.
Requirements & hints:
 You must have a separate header and implementation files for the
above classes.
 A sample inventory.txt file is available.
 The movies/books should be stored in the list in alphabetical
order by barcode.
 Be sure to check for errors: Returning an item that is not
supported by the store, checking out an item that is not
supported by the store, inquiring about an item that is not
supported by the store, etc.
 In this program, you may need to use the function typeid to
obtain the runtime type of variables/pointers. The following is a
sample code of using typeid.
#include <typeinfo
void print(StoreItem *item)
{
Movie defaultMovie; // a movie object
Book defaultBook; // a book object
if ( typeid(*item) == typeid(defaultMovie) )
{cout << “item is a movie pointer” << endl;
cout << “The director of the movie is “
<< ((Movie *)item)-getDirector() << endl;
}
else if ( typeid(*item) == typeid(defaultBook) )
{
cout << “item is a book pointer” << endl;
cout << “The author of the book is “
<< ((Book *)item)-getAuthor() << endl;
}
}
 In this program, you may need to use the stringstream to
implement the function createFromString in classes Book and
Movie. To user string stream, you need to include the header file
sstream. The following statement creates a string stream from an
string object. The usage of stringstream is similar to a cin.
#include <sstream
stringstream ss(aStringVariable);
ss aVariable;
getline(ss, stringVariable2HoldValue, ‘|’);