Description
2 Learning Outcomes
In this assignment you will learn to
1. Use operator overloading (with polymorphism).
2. Use templates to (finally) achieve data abstraction.
3. Use multiple inheritance in a diamond hierarchy.
4. Use Factories to separate object creation from application logic.
3 Overview
In this assignment we will use a similar framework to Assignment 2, the PhotoGram application. Our previous
version was not entirely realistic (to put it lightly). In this version we will have a master list of Photos, and use
these Photos to create Albums. A Photo can appear in more than one Album. Deleting an Album should no longer
delete the Photos contained in them (in fact, in this version, to keep it simple, we will only delete Photos when
the application exits – you still must have no memory leaks). Because we may add Photo and Album subclasses
in the future, and because their creation can involve disk access (downloading from SD card or phone for example),
we will use a MediaFactory to create these objects.
We are also implementing a simple search function for Photos. This will allow us to find Photos with certain
Criteria and add them to an Album. We will use a Criteria class which encapsulates the search details and allow us
to add future search Criteria without changing the core algorithm. We will also use a proper templated collection
class that we will write ourselves.
4 Classes Overview
This application will consist of 9 base classes and 3 derived classes (of the Criteria class).
1. The Date class (Entity object):
(a) Store information about Dates.
2. The Array class (Container object):
(a) An abstract container for data with overloaded operators.
3. The Photo class (Entity object):
(a) Contains information about a particular photo.
4. The Album class (Entity object):
(a) Contains information about the album.
(b) Maintains a collection of Photos.
5. The Criteria class (Entity object):
(a) This class is used to match user searches to matching Photo objects. There are an additional three derived
classes arranged in a diamond hierarchy, Cat_Criteria (category), Date_Criteria, and CandD_Criteria
(both date and category).
6. The MediaFactory class (Boundary object):
(a) This class is used to create Photos, Albums, and Criteria objects. It separates our application logic from
the creation of Photos, Albums, or Criteria types.
7. The PhotoGram class (Container/Control object):
(a) This class contains the master list of Photos and a collection of Albums. Users can add Photos to the
master list, and add or remove Albums. In addition we can search for Photos and these Photos can be
added to an Album (we will not worry about removing Photos from an Album in this assignment). In
addition, in conjunction with the AlbumCreator and View objects, users can browse Albums and Photos.
8. The AlbumCreator class (Control object):
(a) Controls the interaction of PhotoGram with the View.
(b) Maintains its own list of Photos found during the latest search.
9. The View class (Boundary object):
(a) Prints menus, Albums, or Photos, and takes input.
5 Instructions
Download the starting code from Brightspace. It includes some global functions that you are to use for testing. All
member variables are private unless otherwise noted. All member functions are public unless otherwise noted.
Some return values are not explicitly given. You should use your best judgment (they will often be void, but not
always). Unless otherwise specified ALL CLASSES SHOULD OVERRIDE THE << OPERATOR. This function
should display the metadata of the class using appropriate formatting.
Your finished code should compile into a single executable called a4 using the command make a4 or simply
make. Your submission should consist of a single zip file with a suitable name (e.g., assignment4.zip) that contains
a folder containing all your files. This folder should also contain a README with your name, student number, a list
of all files that are included, a directory structure (if applicable), compiling and running instructions, and any other
information that will make the TAs life easier when they mark your assignment.
5.1 defs.h
You should initialize the arrays to the sizes given in this file.
5.2 The Date Class
Make the following changes to the Date class:
1. Overload the <, and == and <= operators, and any other comparison operators that you feel you will need.
2. Overload the stream insertion (<<) operator.
5.3 The Photo Class
Make the following changes to the Photo class:
1. Member variables:
(a) Add a string category member variable.
2. In the constructor, add a string parameter for category just after the title. Thus your constructor should
take the arguments in this order: title, category, date, content.
3. Make getters for category and date.
4. Have the print and display functions take an ostream as an argument and have them write to the ostream
instead of std::cout.
5. Overload the stream insertion (<<) operator.
Your header member functions should look like the following:
Photo ( const string & title , const string & category , const Date & , const string & content );
bool equals ( const string & title ) const ;
const Date & getDate () const ;
const string & getCategory () const ;
void print ( ostream &) const ;
void display ( ostream &) const ;
5.4 The Criteria Classes
The Criteria class is an abstract class with 3 concrete derived classes.
5.4.1 The Criteria Abstract Class
1. Make a pure virtual function bool matches(const Photo&).
2. Make a pure virtual print function that takes an ostream as an argument.
3. Implement the stream insertion operator << using polymorphism.
5.4.2 The Cat_Criteria Class
Make a class Cat_Criteria that is a derived class of Criteria using virtual inheritance.
1. Make a private member variable string category.
2. Have the constructor take a string argument and initialize the category member.
3. Override the matches function so that it returns true if the Photo::category matches the category member.
4. Override the print function so that it tells the user how this Criteria will match a Photo. Be sure to print
out the category somewhere in there (we will be looking for it in the tutorial).
5.4.3 The Date_Criteria Class
Make a class Date_Criteria that is a derived class of Criteria using virtual inheritance.
1. Make two private member variables, a start Date and an end Date. This represents a range of Dates.
2. Have the constructor take two Dates, start and end, in that order.
3. Override the matches function so that it returns true if Photo::date is greater than or equal to the start
Date and less than or equal to the end Date.
4. Override the print function so that it tells the user how this Criteria will match a Photo. Be sure to print
out both Dates (we will be looking for it in the tutorial).
5.4.4 The CandD_Criteria Class
Make a class CandD_Criteria that is a derived class of both Date_Criteria and Cat_Criteria.
1. Have the constructor take a Date start, Date end and string category arguments, in that order, and
initialize the members.
2. Override the matches function so that it returns true if the Photo::category matches the category member
and Photo::date is greater than or equal to the start Date and less than or equal to the end Date
3. Override the print function so that it tells the user how this Criteria will match a Photo. Be sure to print
out the category and both Dates somewhere in there (we will be looking for it in the tutorial).
5.5 The Array Class
The array class is provided for you, but it currently only works for ints. Make the following modifications. Also
note that both the class definition and implementation are in the same .h file, and since we are making it into a
template, you should leave it that way.
1. Convert the Array class to a Template class so that it may store any type.
2. Change the get method into a method that overloads the [] operator. Make two versions of this function,
one const and one not const. If the supplied index is out of bounds, print an error message to cerr and call
exit(1) (which will exit the program).
3. Overload the += operator so that you can add an element to Array. If there is room this should add an element
to the back of the array. If there is no room do nothing. Be sure to enable chaining.
4. Overload the -= operator so that you can remove an element from the Array. If the element is found remove
it. Be sure to enable chaining.
5. Add a clear function that removes everything from the Array.
5.6 The Album Class
The major changes to this class are
• Replacing PhotoArray with Array
• We no longer specify the order of the Photos by adding at an index. The Photos will simply be stored in the
order they are added (i.e., we add Photos to the back of the Array).
• You should not delete any Photos in this class. This is the responsibility of PhotoGram and the master list of
Photos.
The changes outlined below will reflect that. Make the following changes to the Album class:
1. Member variables:
(a) Replace PhotoArray with Array
2. Remove the copy constructor.
3. Have the bool addPhoto(Photo*) function add the Photo* to the back of Array.
4. Remove the bool addPhoto(int index, Photo*) function.
5. Make an int size() function that returns the number of Photos in this Album.
6. Modify the print() and display() functions to accept an ostream argument. Have the data printed to the
ostream argument instead of std::cout. As a reminder:
(a) The print function should print metadata about the Album class, including the number of Photos.
(b) The display function should print metadata about the Album class as well as display each Photo.
7. Overload the stream insertion operator << to call the print function.
Your header member functions should look like the following:
Album ( const string & title , const string & description );
bool equals ( const string & title ) const ;
void addPhoto ( Photo *);
Photo * getPhoto (int) const ;
int size () const ;
void print ( ostream &) const ;
void display ( ostream &) const ;
5.7 The MediaFactory Class
The header for this class is provided. In addition the uploadPhoto implementation is provided.
This Factory class reflects that creating a Photo object is unlikely to be a simple call to the constructor. We
may have to, for example, load an image file from disk to create it. Here we are using simulated image files (the
content member) but the principle is the same.
A similar principle applies to the Criteria class. At some point we might want to introduce more search
criteria.
1. toDate and uploadPhoto have been done for you. Complete the rest of the function implementations (they
are as simple as they look).
5.8 The PhotoGram Class
The new specification for PhotoGram is as follows:
1. Member variables:
(a) Replace AlbumArray with Array
(b) Add a master list of Photos using Array
(c) Add a MediaFactory – you will use this to create all objects used in PhotoGram.
2. Member functions:
(a) addAlbum: This should take a title and description as arguments. Use MediaFactory to make a new
Album and add it to the collection of Albums.
(b) Update Mar 21: addToAlbum: This should take an int index and an Array
Photos in the Array should be added to the Album located at the given index.
(c) uploadPhoto: This should take a title as an argument. Use MediaFactory to make a new Photo and
add it to the list.
(d) deleteAlbum(int index): Attempt to remove and delete the Album at the given index. If it is a bad
index give an error message and return.
(e) getPhotos: This should take a Criteria object and an Array
in the master list that match the Criteria should be added to the Array
– simply add their pointers to the Array
3. The following functions will make use of the View class for printing and displaying Albums and Photos. Your
functions should forward their calls to the similar View functions. This is known as double-dispatching, and it
is a popular design pattern for drawing objects on a View:
(a) void displayAlbum(int index, View&): display the Album at the given index using the View. Output
an error message if the index is out of bounds.
(b) int printAlbums(View&): Forward this call to the View. Return the number of Albums currently stored
in PhotoGram.
(c) void displayPhoto(int index, View&): display the Photo at the given index on the View. Output an
error message if the index is out of bounds.
(d) int printPhotos(View&): Forward this call to the View. Return the number of Photos currently stored
in PhotoGram.
5.9 The View Class
The View class is done for you.
5.10 The AlbumCreator Class
Most of the AlbumCreator class is done for you.
1. Write the implementation of the addAlbum function.
2. Write the implementation of the deleteAlbum function. It should function similarly to the displayAlbum
function in that it should print all Albums, prompt the user for their choice, then delete the Album at the index
indicated. It should only be a few lines of code, and you should be calling existing functions wherever possible.
5.11 The main Function
This has also been provided for you. It instantiates a AlbumCreator object and calls launch.
6 Grading
The marks are divided into three main categories. The first two categories, Requirements and Constraints are
where marks are earned. The third category, Deductions is where you are penalized marks.
6.1 Specification Requirements
These are marks for having a working application (even when not implemented according to the specification, within
reason). These are the same marks shown in the test suite, repeated here for convenience. Marks are awarded for
the application working as requested.
The test script provides a mark out of 20. If you have implemented everything correctly, this will probably be
your mark. However, you are still responsible for, and may be penalized for, any errors the test suite does not catch,
and drastic departure from the specification may still result in a penalty (such as using outside libraries). As such, we
reserve the right to modify the mark given by the test script in the event that your code has errors or uses forbidden
libraries.
General Requirements
• All marking components must be called and execute successfully to earn marks.
• All data handled must be printed to the screen to earn marks (make sure print, display, and the stream
insertion operator << print useful information).
6.1.1 Application Requirements: 26 marks
Important: To get the marks for application requirements, you had to have implemented these classes with the
Array
If you use the data structures from Assignment 2 then you get 0.
The marks below are based on the correct execution of each of the menu items.
• 2 marks: Add Album works correctly.
• 2 marks: Delete Album works correctly.
• 2 marks: All Albums are printed correctly.
• 2 marks: A single Album is displayed correctly.
• 2 marks: All Photos are printed correctly.
• 2 marks: A single Photo is displayed correctly.
• 2 marks: Getting photos by category works correctly.
• 2 marks: Getting photos by date works correctly.
• 4 marks: Getting photos by date and category works correctly.
• 2 marks: Print current Photo list works correctly.
• 2 marks: Display current Photo list works correctly.
• 2 marks: Add current Photo list to Album works correctly.
Requirements Total: 26 marks
6.2 Constraints
The previous section awards marks if your program works correctly. In this section marks are awarded if your
program is written according to the specification and using proper object oriented programming techniques. This
includes but is not limited to:
• Apply “const”-ness to your program.
– Print statements, getters, and any member function that does not change the value of any member variables
should be const.
– Any returned object that will not be changed should be const.
– Any parameter object (passed by reference) that will not be modified should be const.
• Proper declaration of member variables (correct type, naming conventions, etc).
• Proper instantiation of member variables (statically or dynamically)
• Proper instantiation of objects (statically or dynamically)
• Proper constructor and function signatures.
• Proper constructor and function implementation.
• Proper use of arrays and data structures.
• Passing objects by reference or by pointer. Do not pass by value.
• Reusing existing functions wherever possible.
• Proper error checking – check array bounds, data in the correct range, etc.
• Reasonable documentation (remember the best documentation is expressive variable and function names, and
clear purposes for each class – I am not a stickler on this, but if you write code that could be confusing, add
some comments).
6.2.1 Constraint marks:
• 2 marks: Proper implementation of the Date class.
• 2 marks: Proper implementation of the Array class.
• 2 marks: Proper implementation of the Photo class.
• 2 marks: Proper implementation of the Album class.
• 2 marks: Proper implementation of the PhotoGram class.
• 2 marks: Proper implementation of the MediaFactory class.
• 2 marks: Proper implementation of the AlbumCreator class.
• 4 marks: Proper implementation of the Criteria classes.
Constraints Total: 18 marks
Requirements Total: 26 marks
Assignment Total: 44 marks
6.3 Deductions
The requirements listed here represent possible deductions from your assignment total. In addition to the constraints
listed in the specification, these are global level constraints that you must observe. For example, you may only use
approved libraries, and your programming environment must be properly configured to be compatible with the virtual
machine. This is not a comprehensive list. Any requirement specified during class but not listed here must also be
observed.
6.3.1 Packaging and file errors:
1. 5%: Missing README
2. 10%: Missing Makefile (assuming this is a simple fix, otherwise see 4 or 5).
3. up to 10%: Failure to use proper file structure (separate header and source files for example), but your program
still compiles and runs
4. up to 50%: Failure to use proper file structure (such as case-sensitive files and/or Makefile instructions) that
results in program not compiling, but is fixable by a TA using reasonable effort.
5. up to 100%: Failure to use proper file structure or other problems that severely compromise the ability to
compile and run your program.
As an example, submitting Windows C++ code and Makefile that is not compatible with the Linux VM would
fall under 4 or 5 depending on whether a reasonable effort could get it running.
6.3.2 Incorrect object-oriented programming techniques:
• Up to 10%: Substituting C functions where C++ functions exist (e.g. don’t use printf, do use cout).
• Up to 10%: Memory leaks – be sure to check your code with valgrind.
• Up to 25%: Using smart pointers.
• Up to 25%: Using global functions or global variables other than the main function and those functions and
variables expressly permitted or provided for initialization and testing purposes.
6.3.3 Unapproved libraries:
• Up to 100%: The code must compile and execute in the default course VM provided. It must NOT require
any additional libraries, packages, or software besides what is available in the standard VM.
• Up to 100%: Your program must not use any classes, containers, or algorithms from the standard template
library (STL) unless expressly permitted.
