UMBC, CMSC202 Computer Science II, Spring 2007

Due Dates

Design Document: Sunday, April 15, 2007, 11:59pm + 59 seconds

Final Project: Sunday, April 22, 2007, 11:59pm + 59 seconds

Contents

• Objective
• Background
• Assignment
• Grading
• Implementation Notes
• Design Document
• Testing
• Submitting in your program

All of the objects in a RaceCourse will be derived from an abstract base class called Thing (see Thing.h). Cars are simply Things that move; Walls are Things that do not move. Your RaceCourse class will keep track of Things using pointers. By means of virtual member functions, the RaceCourse will allow specialized interaction between the objects without having to "understand" the interaction. (Note: since each Thing has a row and column, the Position class from Project 2 has been eliminated.)

For example, the Thing class has a pure virtual function called DrawMe() which returns a char. The PrettyPrintCourse() member function in Racecourse will use DrawMe() to print out the race course. This will allow us to derive different types of Cars or Things without re-writing PrettyPrintCourse().

One complication we have added is a penalty for cars that bump into another car. When this happens the bumper (the Car that moved) will lose 5 units of fuel and the bumpee (the stationary Car) will gain 5 units of fuel. This fuel deduction will not be handled by RaceCourse. Instead, RaceCourse will call the virtual function encounter() (in the Thing class) to handle the fuel transfer:

Similarly, a RaceCourse no longer needs to worry about a Car winning by reaching the bottom left corner. This will be accomplished by placing a Goal object at bottom left corner (or any place in the race course). When a car bumps into a Goal, the Goal object declares a winner and stops the race. This will allow us to design race courses with goals placed in different locations, or even race courses with several goals, without changing the code for RaceCourse.

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Your main assignment is to design and implement four C++ classes: Car, RaceCourse, PitStop and RandomCar. These are partially specified below.

Requirements for the Car class

The requirements for each function is documented in the skeleton header file Car.h.

Requirements for the RaceCourse class

There is no longer a limit on the number of rows or columns that a race course has. You will need to use dynamically allocated storage to handle this. Whether you use vectors or two-dimensional arrays is up to you. Similarly, there is no limit on the number of Cars (although the client must determine what labels to use).

Note that there is no longer a STALEMATE condition, since a Car that has run out of fuel might regain some when other Cars bump into it. The RaceCourse starts at WAITING, proceeds to STARTED when StartRace() is called and the FINISHED when StopRace() is called.

Note that AddThings() is oblivious of what it is adding. The objects might be Cars, Walls, Goals, ... The Things to be added are given as a const reference vector of Thing pointers. Memory must be allocated for the objects that these pointers point to in the main program. This memory allocation is done outside of the RaceCourse. It is the responsibility of the code that uses RaceCourse to deallocate. RaceCourse only does shallow copying.

Note: AddThings() can be called multiple times when the RaceCourse is in WAITING status. However, after the race has STARTED, no further calls to AddThings() is allowed.

Requirements for the PitStop class

Requirements for the RandomCar class

A Main Program

• A design document is due on Sunday, April 15, one week before the final project. (See the Design Document section.) The design document is 15% of the project grade.

• Projects will be graded on five criteria: correctness, design, style, documentation and efficiency. So, turning in a project that merely "works" is not sufficient to receive full credit.

• Part of your grade will also depend on having demonstrated that you have diligently tested your own program, by creating and submitting your own test main program. (See the Testing section.)

• The Academic Conduct Policy for this course states that programming projects must completed by you own individual effort.

• Remember that the late policy is a 25% penalty for submissions up to 24 hours late. Projects more than 1 day late will receive zero.

1. The following files are provided for you:
   • Thing.h - header file for Thing, Wall and Goal.
   • Thing.cpp - implementation of Thing, Wall and Goal.
   • Car.h - skeleton header file for Car class you must implement. Has comments on the requirements for each member function.
   • Racecourse.h - skeleton header file for RaceCourse class you must implement. Has comments on the requirements for each member function.
   • ScriptedCar.h - header file for class derived from Car. Used by p4main1.cpp.
   • ScriptedCar.cpp - implementation of the ScriptedCar class. Used by p4main1.cpp.
   • p4main1.cpp - Test program.
   • output1.txt - Output from p4main1.cpp
   • p4main2.cpp - Second test program.
   • output2.txt - Output from p4main2.cpp
   • p4main3.cpp - Third test program.
   • output3.txt - Output from p4main3.cpp
   These files are also available on the GL file system in the directory: /afs/umbc.edu/users/c/h/chang/pub/cs202/proj4/

2. Your implementation of Car and RaceCourse must be compatible with the main program and ScriptedCar class provided.

3. Bumping: if a Car only has enough fuel to get to the position next to a Thing, it is not considered to have bumped into that thing. In order to bump into something, the Car must have enough fuel to reach the position of the Thing itself. In either case, the Car is placed in the position adjacent to the Thing, but the encounter() function is only invoked in the second case.

4. In Project 2, GetCar() used a Car index number. There is no longer a concept of a Car index number. The main program creates the Car and passes a pointer (inside a vector) to the RaceCourse.

5. Recall that a car should not be allowed to move if 1) it is out of fuel, 2) the race has not yet started, 3) the race has finished.

6. If your Project 2 did not work and cannot be salvaged, you are permitted to use Prof. Chang's version of Project 2 as a starting point. Send email to him for instructions. [ The Project 2 files are now posted: Car.h, Car.cpp, RaceCourse.h, RaceCourse.cpp, and design.txt. ]

You must submit written responses to these questions by Sunday, April 15, 11:59:59pm. Late submissions are not accepted for design documents.

Answer the following questions using complete English sentences. As usual, grammar and spelling counts. If you remember CUPS = "Capitalization, Usage, Punctuation and Spelling" from elementary school, they certainly apply here.

1. In Project 2, you probably did not represent objects in your race course as pointers. How will the grid of the race course represented now? How will you retrieve the pointer to the "bumpee"?

2. A Thing object stores its position in its data members m_row and m_col. The race course also stores pointers to Things that can be retrieved given the position. Thus, the position of a Thing is stored in two different places. When could you check that these two pieces of information are consistent?

3. Will you have any appendant (non-inherited) data members in Car? If not, where is the fuel level stored? If so, should these members be public, private or protected? Why?

What/how to submit for your design document:

• Download the plain text file: design.txt. The file has the 3 questions listed above.
• Insert your answers in the plain text file using a text editor.
• Submit the text file to the project 'proj4design' using the Unix command: submit cs202 proj4design design.txt
• You do not need submit any header files. Please do not submit any MS Word files, PDF files, ... Just plain text, please.

Warning: When your project is graded, it will also be tested with additional main programs. So, having a project that works with these programs is not a 100% guarantee. Your project must also satisfy the requirements specified above.

• p4main1.cpp    Sample output from p4main1.cpp: output1.txt.

  Note: This test program can be made "interactive" by defining "VT100" using #define.

• p4main2.cpp    Sample output from p4main2.cpp: output2.txt.
• p4main3.cpp    Sample output from p4main3.cpp: output3.txt.

Use the UNIX submit command to turn in your project. The project name for Project 4 is 'proj4'. So, the Unix command will look like:

You should submit the following files. Please follow the spelling and capitalization for these files exactly. It allows us to use a script to compile your programs.

• Car.h: Header file for the Car class.

• Car.cpp: Implementation file for the Car class.

• RaceCourse.h: Header file for the RaceCourse class.

• RaceCourse.cpp: Implementation file for the RaceCourse class.

• PitStop.h: Header file for the PitStop class.

• PitStop.cpp: Implementation file for the PitStop class.

• RandomCar.h: Header file for the RandomCar class.

• RandomCar.cpp: Implementation file for the RandomCar class.

• mymain.cpp: Your main program for testing PitStop and RandomCar.

• Any other files needed to compile and run your program.