Freedom of Movement programmign assignment AP-A

Download the following files and place them in a folder called Movement

• display.cpp
• display.h
• environ.cpp
• environ.h
• fish.cpp
• fish.h
• fishsim.cpp
• nbrhood.cpp
• nbrhood.h
• position.cpp
• position.h
• randgen.cpp
• randgen.h
• simulate.cpp
• simulate.h
• utils.cpp
• utils.h
• fish.dat

Create new LJHS project called HexGrid and store the project in the Movement folder. Move fish.dat into the HexGrid folder. Add all *.cpp files to your project then run the project. Ignore any warnings invloving RandGen. You should get a two-dimensional array display.

Instead of displaying spaces between the fishes in the output, display a dot ('.') for the space. Determine which class needs to be editied and then edit the file so that dots '.''s are output instead of blank spaces.

In order to change the behavior of each fish as requested by the biologists, we need to modify the relationships among the positions. We also need to determine how we can compactly represent a hexagonal grid, where each position has six neighbors. It turns out that the idea of the representation is easy. We store the positions in a two dimensional array as we did before, but we interpret each position in the array differently. If we orient the hexagonal grid as shown below, then each position has one neighbor to the right and one to the left in its own row, but two neighbors in the row above and two neighbors in the row below in directions naturally designated Northeast, Northwest, Southeast and Southwest. For example, the 5 x 4 grid shown below has the odd numbered columns shaded for clarity. Notice how the indexing of the Northeast, Northwest, Southeast and Southwest neighbors of a position depends on whether that position is an even or an odd numbered row. The diagram has the position (2, 2) indicated by an X and its six neighbors designated by NE, E, SE, SW, W, NW.

If we examine the classes making up the fish simulation program, we see the the relationship between neighbors in the two dimensional grid is effectively defined by the four Position member functions North, East, South, West. These functions are called in the Fish class member function EmptyNeighbors, which constructs a Neighborhood containing the positions to which the fish can move. Consequently, we can change the internal representation of the fish grid to a hexagonal grid by simply changing these functions appropriately. In the course of doing this we note that a small change must be made in the Neighborhood class implementation to accomodate the larger number of neighbors now possible and an adjustment to the Display class is needed to represent the new grid on screen.

Before writing code you should plan your changes. Look at the 'Class Diagrams' and plan your course of action. Draw modified versions of the Fish and Position class diagrams to reflect the changes that you make. Show me your changed diagrams before starting the program.

1. Prepare a plan for your modifications, as outlined below. Modify the Fish and Position class diagrams and show them to me before starting any of the below programming!
2. Replace the four direction functions in the Position class with six functions representing the six hexagonal grid directions.
3. Modify the Fish member function EmptyNeighbors to create a Neighborhood containing all the empty neighbors of this Fish, according to the six directions specified by the Position functions.
4. Change the maximum number of Positions that can be stored in a Neighborhood so that all the neighbors can be accommodated. The current implementation of Neighborhood uses an explicit constant (4) in the Neighborhood constructor. In general, this is a poor design. It is better to use a named constant or to pass the value as a parameter to the Neighborhood constructor. Where would a constant specifying the number of neighbors naturally occur? Declare such a constant with value 6 and use it in place of the explicit 4.
5. The display can approximate a hexagonal grid by indenting the odd rows half the width used for a cell. This means that for the character-based Display class that is part of thte MBCS, the WIDTH constant should be set to an even value (2 works well), and when displaying an odd row of the hexagonal grid, WIDTH/2 spaces should be inserted into the cout stream. Modify the Display class so that it displays a hexagonal grid.

What to turn in

1. Cover page with the title, date and your name.
2. Your modified Class Diagrams. They can be hand drawn if they are done neatly!
3. Wtite a report explaining the problem and how you solved it. You also need to include in your report what class you created the "Number of Neighbors" constant in.
4. Output should include the original location of the fish loaded in by the fish.dat file, and the location of the fish after one step.
5. Listing of all files you changed with noticeable comments specifing your changes. Use a highlite marker and higlite all your changes/additions.