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that calculates the late fees for the rental. In your
main
method, create an array of
type
Rental
filled with sample data of all types of movies. Then, create a method
named
lateFeesOwed
that iterates through the array and returns the total amount
of late fees that are outstanding.
4. The goal for this programming project is to create a simple 2D predator-prey
simulation. In this simulation, the prey is ants, and the predators are doodlebugs.
These critters live in a world composed of a 20
20 grid of cells. Only one critter
may occupy a cell at a time. The grid is enclosed, so a critter is not allowed to move
off the edges of the grid. Time is simulated in time steps. Each critter performs
some action every time step.
The ants behave according to the following model:
•
Move. Every time step, randomly try to move up, down, left, or right. If the
cell in the selected direction is occupied or would move the ant off the grid,
then the ant stays in the current cell.
•
Breed. If an ant survives for three time steps, then at the end of the third time
step (i.e., after moving), the ant will breed. This is simulated by creating a new
ant in an adjacent (up, down, left, or right) cell that is empty. If there is no
empty cell available, no breeding occurs. Once an offspring is produced, the
ant cannot produce an offspring until three more time steps have elapsed.
The doodlebugs behave according to the following model:
•
Move. Every time step, if there is an adjacent cell (up, down, left, or right)
occupied by an ant, then the doodlebug will move to that cell and eat the ant.
Otherwise, the doodlebug moves according to the same rules as the ant. Note
that a doodlebug cannot eat other doodlebugs.
•
Breed. If a doodlebug survives for eight time steps, then at the end of the time
step, it will spawn off a new doodlebug in the same manner as the ant.
•
Starve. If a doodlebug has not eaten an ant within the last three time steps,
then at the end of the third time step, it will starve and die. The doodlebug
should then be removed from the grid of cells.
During one turn, all the doodlebugs should move before the ants.
Write a program to implement this simulation and draw the world using ASCII
characters of “o” for an ant and “X” for a doodlebug. Create a class named
Organism
that encapsulates basic data common to both ants and doodlebugs.
This class should have an overridden method named
move
that is defined in the
derived classes of
Ant
and
Doodlebug
. You may need additional data structures to
keep track of which critters have moved.
Initialize the world with 5 doodlebugs and 100 ants. After each time step, prompt
the user to press Enter to move to the next time step. You should see a cyclical pat-
tern between the population of predators and prey, although random perturbations
may lead to the elimination of one or both species.
5. Consider a graphics system that has classes for various figures—say, rectangles,
boxes, triangles, circles, and so on. For example, a rectangle might have data
