Description
1. Problem Description
This project simulates interactions among different forms of life in a plain. The plain is
represented by an πο΄π grid that changes over a number of cycles. Within a cycle, each square
is occupied by one of the following five life forms:
Badger (B), Fox (F), Rabbit (R), Grass (G), and Empty (E)
An Empty square means that it is not occupied by any life form.
Below is a plain example as a 6 ο΄ 6 grid.
F5 E E F0 E E
B3 F1 B0 R0 G R0
R0 E R2 B0 B2 G
B0 E E R1 F0 E
B1 E E G E R0
G G E B0 R2 E
Both row and column indices start from 0. In the example, the (1, 1)th square is occupied by a
1-year-old Fox. It has a 3 Γ 3 neighborhood centered at the square:
F5 E E
B3 F1 B0
R0 E R2
The (0, 0)th square F5 (a 5-year-old Fox) has only a 2 Γ 2 neighborhood:
F5 E
B3 F1
Meanwhile, the (2, 0)th square R0 (a newborn Rabbit) has a 3 Γ 2 neighborhood:
B3 F1
R0 E
B0 E
Generally, the neighborhood of a square is a “3 Γ 3” grid which includes only those squares
lying within the intersection of the plain with a 3 Γ 3 window centered at the square. When a
square is on the border, the dimension of its neighborhood reduces to 2 Γ 3, 3 Γ 2, or 2 Γ 2.
2. Survival Rules
The plain evolves from one cycle to the next one. In the next cycle, the life form to reside on a
square is decided from those life forms in the current cycle who live in the 3 Γ 3 neighborhood
centered at the square, under a set of survival rules. These rules are specified according to the
life form residing on the same square in the current cycle. Badgers, foxes, and rabbits start at
age 0, and grow one year older when the next cycle starts.
2.1 Badger
A badger dies of old age or hunger, or from a group attack by foxes when it is alone. The life form
on a Badger square in the next cycle will be
a) Empty if the Badger is currently at age 4;
b) otherwise, Fox, if there is only one Badger but there are more than one Fox in the
neighborhood;
c) otherwise, Empty, if Badgers and Foxes together outnumber Rabbits in the neighborhood;
d) otherwise, Badger (the badger will live on).
The new life form taking over the square, if a Fox, will have age 0 when the next cycle starts.
For example, in the following neighborhood of a Badger at age 2:
R0 G R0
B0 B2 G
R1 F0 E
there are two Badgers (including self), one Fox, three Rabbits. Going down the rule list, neither
a), b), c) applies. According to rule d), the central element (square) will still be B (Badger) — just
one year older — in the next cycle. In other words, B2 will be replaced with B3.
2.2 Fox
A fox dies of old age, hunger, or an attack by more numerous badgers. The life form on a Fox
square in the next cycle will be
a) Empty if the Fox is currently at age 6;
b) otherwise, Badger, if there are more Badgers than Foxes in the neighborhood;
c) otherwise, Empty, if Badgers and Foxes together outnumber Rabbits in the neighborhood;
d) otherwise, Fox (the fox will live on).
The new life form, if a Badger, will have age 0 when the next cycle begins.
For example, in the following neighborhood of a Fox at age 1:
F5 E E
B3 F1 B0
R0 E R2
there are two Foxes, two Badgers, and two Rabbits. Rule c) applies. The central square will
become E in the next cycle.
2.3 Rabbit
A rabbit dies of old age or hunger. It may also be eaten by a badger or a fox. More
specifically, the life form on a Rabbit square in the next cycle will be
a) Empty if the Rabbit’s current age is 3;
b) otherwise, Empty if there is no Grass in the neighborhood (the rabbit needs food);
c) otherwise, Fox if in the neighborhood there are at least as many Foxes and Badgers
combined as Rabbits, and furthermore, if there are more Foxes than Badgers;
d) otherwise, Badger if there are more Badgers than Rabbits in the neighborhood;
e) otherwise, Rabbit (the rabbit will live on).
If the new life form is a Badger or Fox, it will have age 0 when the next cycle starts.
In the following neighborhood of a rabbit at age 2:
F1 B0 R0
E R2 B0
E E R1
lives two Badgers, one Fox, and three Rabbits. Rule a) does not apply because the Rabbit is
only 2-years old. Rule b) does since there is no Grass in the neighborhood. The central element
(square) will be E in the next cycle according to this rule.
2.4 Grass
Grass may be eaten out by overcrowded rabbits. Rabbits may also multiply fast enough to take
over the Grass square. In the next cycle, the life form on a Grass square will be
a) Empty if at least three times as many Rabbits as Grasses in the neighborhood;
b) otherwise, Rabbit if there are at least three Rabbits in the neighborhood;
c) otherwise, Grass.
If the new life form is a Rabbit, it will be aged 0 when the next cycle starts.
For example, if the neighborhood of a Grass is
F0 E E
R0 G R0
B0 B2 G
the central element will be G in the next cycle under rule c).
2.5 Empty
Empty squares are competed by other life forms. More specifically, the life form on an Empty
square in the next cycle will be
a) Rabbit, if more than one neighboring Rabbit;
b) otherwise, Fox, if more than one neighboring Fox;
c) otherwise, Badger, if more than one neighboring Badger;
d) otherwise, Grass, if at least one neighboring Grass;
e) otherwise, Empty.
If the new life form is a Badger, Fox, or Rabbit, it will have age 0 when the next cycle begins.
For example, an Empty square in the top row has the following neighborhood:
F0 E E
R0 G R0
which includes two Rabbits. Thus, rule a) applies to change the central element to R0 in the next
cycle.
3. Task
You will implement an abstract class Living to represent a generic life form. It has three
subclasses Animal, Empty, and Grass. The first subclass, implementing the interface MyAge, is
abstract, and needs to be extended to three subclasses: Badger, Fox, and Rabbit. You also
need to implement a Plain class which has a public member Living[][] to represent a grid
plain.
The class Wildlife repeatedly simulates evolutions of input plains, either randomly generated
or read from files. In each iteration, it interacts with the user who chooses how the plain will be
generated, and enters the number of cycles to simulate. The iteration prints out the initial plain
and the final plain.
Your random plain generator may follow the uniform probability distribution so that Badger,
Empty, Fox, Grass, and Rabbit have equal likelihoods to occupy every square. Or you may use a
different distribution, as long as no life form has zero chance to appear on a square.
Java provides a random number generator. To use it, you need to import the package
java.util.Random. Next, declare and initiate a Random object like below
Random generator = new Random();
Then, every call below
generator.nextInt(5)
will generate a random number between 0 and 4 that corresponds to one of the five life forms.
Plain creation from an input file will weigh more than random creation in our grading. When
zero or a negative number of cycles is entered by the user, your code does nothing but waits for
a positive input.
A new living form, if a Badger, Fox, or Rabbit, has age 0 at its creation, whether initially by the
class plain or later on under a survival rule. After surviving a cycle, its age increases by one.
Templates are provided for all classes. Be sure to use the package name
edu.iastate.cs228.hw1 for the project.
Below is a sample simulation scenario over three initial plains. In the first iteration, the user
entered 1 for a randomly generated plain, 3 to specify the grid to be 3ο΄3, and 1 to simulate just
one cycle. The simulator printed out the initial and final plains. The second iteration simulated a
randomly generated 6ο΄6 grid over 8 cycles. In the third iteration, the user typed 2 for a file
input, entered the file name “public3-10×10.txt”, and specified 6 cycles. (The file public3-
10×10.txt resides in the same folder containing the src folder.) After the third iteration, the
user typed 3 to end the simulation. (Any number other than 1 and 2 could have ended the
simulation.)
Simulation of Wildlife of the Plain
keys: 1 (random plain) 2 (file input) 3 (exit)
Trial 1: 1
Random plain
Enter grid width: 3
Enter the number of cycles: 1
Initial plain:
R0 R0 B0
G G E
G E G
Final plain:
R1 R1 B1
G G G
G G G
Trial 2: 1
Random plain
Enter grid width: 6
Enter the number of cycles: 8
Initial plain:
E E G R0 B0 G
G G R0 B0 F0 R0
G E E R0 G E
R0 G R0 R0 B0 R0
F0 E R0 G R0 F0
R0 R0 F0 F0 G F0
Final plain:
R0 E R0 E B3 G
E E E R0 R1 R3
R0 R0 R0 E E R0
E E E E R0 G
R0 E E R0 G G
E R0 R0 F1 G G
Trial 3: 2
Plain input from a file
File name: public3-10×10.txt
Enter the number of cycles: 6
Initial plain:
B0 E B0 E B0 R0 E R3 E G
G E B0 E F0 R0 E B4 G G
G G G G E E R0 E G G
F0 E G G E R0 R0 B0 B0 G
F0 F1 E E E E E E B0 E
G G R1 R0 R0 R0 R0 B0 B0 E
E G R0 R1 R2 R2 G E G G
B0 B0 G R0 R0 R0 G B0 E G
E G G F4 R2 R0 E G G G
G G E E E G G G G G
Final plain:
B0 E B0 E E R0 E R0 R2 E
G E B0 R0 B4 R0 E R0 R3 R1
G G R2 R0 E R0 R0 E E E
G F5 R3 R0 E R0 R0 E E R0
R2 E E E R0 R0 E E B1 G
R0 R0 R0 R0 R0 E B1 R0 G G
E E R0 E R0 E B1 R0 G G
B4 E R0 E R0 E E E R0 G
G R2 R3 E R0 E R0 R3 R1 G
G R0 R1 E R0 E R0 R2 R0 G
Trial 4: 3
Your code should print out the same text messages for user interactions.
4. Input/Output Format
The format for plains is shown in the sample runs above. Every square occupies two spaces
starting with one of the letters βBβ, ‘E’, ‘F’, ‘G’, and ‘R’. If the letter is βBβ, ‘F’, or ‘R’, then it is followed
by a digit representing the animalβs age; otherwise, it is followed by a blank. There is exactly
one blank between two squares, whether represented by a letter and a digit, or a letter and a
blank. No blank lines.
You may assume all input files to be correctly formatted, containing βBβ, ‘E’, ‘F’, ‘G’, ‘R’, and digits
up to 6 as the only non-blank characters. No digit will exceed the lifespan of the animal
represented by its preceding letter.
5. Junit Classes
JUnit classes include AnimalTest, BadgerTest, EmptyTest, FoxTest, GrassTest, LivingTest,
PlainTest, RabbitTest, and WildlifeTest. You need to implement all these classes.
6. Submission
Write your classes and JUnit test classes in the edu.iastate.cs228.hw1 package. Also submit
the text files with your JUnit tests. Turn in the zip file not your class files. Please follow the
guideline posted under Documents & Links on Canvas.
Include the Javadoc tag @author in each class source file. Your zip file should be named
Firstname_Lastname_HW1.zip.
