Project 2

Due: Sunday June 19th, (11:59 PM) (15 Extra Credit for Submitting by Thursday June, 16th -- 10 project / 5 Midterm)

Objective

This assignment will give you practice with:

composition of objects
operator overloading
dynamically allocating arrays of objects

Task

You will be writing a class that represents a play list of songs. Your play list class will manage a dynamically allocated array of song objects. The Song class is provided for you:
song.h
song.cpp

You should not change these files. I will test your programs using these originals.

You will write a class called PlayList implemented in files playlist.h and playlist.cpp.

Your PlayList class will support two basic uses:

Mangaing the play list. This includes adding and deleting songs.
Playing from the play list. This includes keeping track of which is the next song to be played and supporting different playing modes (such as normal and repeat). Obviously we will not actually be playing any music. "Playing" the song will consist of printing the name.

Program Details and Requirements:

There is no size limit on the play list, so it should be implemented with a dynamically allocated array. There should never be more than 5 unused slots in the array (ie the number of allocated spaces may be at most 5 larger than the number of slots that are actually filled with real data. Whenever the array is resized, print a message (for testing purposes) that states that the array is being resized, and what the new size is. Example: "** Array being resized to 10 allocated slots **". Correct memory management should be used, including the cleanup of memory (i.e. you must program the class so that it leaves no "memory leaks"). This means that you need to deallocate any dynamic space, when and where appropriate.

Your class must provide the following member functions:

AddSong
This function will take a Song object as a parameter and insert it into the play list.

DeleteSong
This function will take a Song object as a parameter and search the play list for it. If it is found, it should be removed and the function should return true. If it is not found, a value of false should be returned. If the play list has multiple copies of one song, you should just delete all copies.

Intersect
This function will take a Playlist object as a parameter and return a new playlist that is the intersection of the songs in the playlist argument (the playlist passed in by the caller) and the songs contained within the playlist object in which Intersect been called (calling object). That is, the new playlist will contain all songs that are common to both playlists (with no duplicates).

ShowAll
This function will print all of the songs in the play list to the screen.

SetMode
This function will change the playing mode of the play list. Your class will have to keep track of the playing mode and the song that is currently being played. The three modes are:

Mode	Meaning
NORMAL	After playing this song, the next song to be played is the next sequential song. For example after playing song with index 7, the next song to be played is the song at index 8. If the last song is played, the next song should be song 0.
REPEAT	After playing this song, the next song to be played will still be this song.

The mode should be defined with the following enumeration in your playlist.h file:

enum Mode
{
  NORMAL,
  REPEAT
};

Play
This function will play one song from the play list. This simply involves printing a message along with the song name. The first time the Play function is called, it should play the song at index 0. Later calls should play other songs depending on the current mode.

Your class must also overload the following operators and implement the described functionality accordingly:

Addition operator (+)
The addition operator will have two meanings depending on the arguments supplied by the caller:
- adding a song to a playlist (i.e. playlist object + song object)
  This version will return a new playlist object. The returned playlist will be a concatenation of all songs in the caller's playlist and the single song. The single song object will be at the end of the newly created playlist.
- adding two playlists (i.e. playlist object + playlist object)
  This version will also return a new playlist object. The returned playlist will be a concatenation of the two playlist objects passed in by the caller.
Subtraction operator (-)
The subtraction operator will have only one meaning:
- removing a song(s) from a playlist (i.e. playlist object - song object)
  This version will return a new playlist object. The returned playlist will be all songs in the caller's playlist with any instances of the song passed in by the caller removed.

In addition to these functions, your class must provide any other functions that are needed to ensure that the memory handling is safe and correct. Your class should not produce memory leaks or segmentation faults under any circumstances!

Test Program

I've created a menu program that will help you interactively test the features of your PlayList class. You can get a copy of menu.cpp here.

This program will allow you to interactively test the features of your PlayList class. Keep in mind that this program does not test everything that your class must handle. For example, it doesn't test the copy constructor or the operator overloads. You should write other tests that verify you are implementing your memory allocation and deallocation correclty.

General Requirements:

No global variables, other than constants
All member data of your class must be private
Use the const qualifier on member functions and parameters wherever it is appropriate.
When you write source code, it should be readable and well-documented.
Your playlist.h file should contain the class declaration only. The playlist.cpp file should contain the member function definitions.

Hints:

Separate the memory management code from the rest. You can do this by creating extra private member functions to handle dynamic re-sizing of the array.
Concentrate on writing the functions that manage memory before writing the other functions. It is harder to debug a program that has memory errors.

For Project 2, submit the following files via PyGrader:

 
  playlist.h
  playlist.cpp