Description
Abstract Implement a simple 2D predator-prey simulation using derived classes and virtual functions. Outcomes After successfully completing this assignment, you should be able to:– Design an abstract base class and several derived classes from the base class. Design one or more virtual functions in the base class and provide concrete implementations of them in the derived classes. Enumerate the objects and invoke a method on each one. Before Starting Read Chapters 14 and 15 of Absolute C++, which introduce inheritance and polymorphism, respectively. This assignment is adapted from Programming Project 3 of Chapter 15. Depending upon your approach to this assignment, you may also find the following useful:– §7.3 about vectors and §17.3 about iterators. Teams: You may optionally work in two-person teams. To register your team in Canvas, please send an e-mail to cs2303-staff@cs.wpi.edu. Your team should make one joint submission, and the names of both team members must be on each file. Existing teams from Programming Assignment #5 will be carried over to this assignment. If you wish to dissolve or change teams, please send e-mail to the same address. This Assignment This program involves a simulation of a grid of n-by-n squares, some of which may be occupied by organisms. There are two kinds of organisms — doodlebugs (the predators) and ants (the prey). Only one organism may occupy a cell at a time. Time is simulated in steps. Each organism attempts to perform some action every step. No action may cause an organism to move off the edges of the grid. Ants behave as follows:– Move. For every step, each ant enumerates its adjacent cells — up, down, left, or right — and randomly selects an unoccupied one that is on the grid. If all adjacent cells are occupied or off the edges of the grid, the ant does not move but rather remains in its current location. 0F1 Breed. If an ant survives for at least three time steps, at the end of the third time step (i.e., after moving) the ant gives birth to a new ant in an adjacent cell (i.e., up, down, left, or right). If 1 You will have to establish a systematic way of ordering the actions of the ants. Obviously, a previous ant could move into the only possible space available to another ant, thereby preventing the second one from moving.
more than one empty cell is available, it chooses one at random. If no empty cell is available, no birth occurs.1F2 Once an offspring is produced, an ant cannot produce another offspring until it has survived three additional steps.2F3 Doodlebugs behave as follows:– Move. For every time step, each doodlebug moves to an adjacent cell containing an ant and eats that ant. If more than one adjacent cell contains an ant, one is chosen at random. The ant that was eaten is removed from the grid. If no adjacent cell (i.e., up, down, left, or right) contains an ant, the doodlebug moves according to the same rules as ants. Note that a doodlebug cannot eat another doodlebug. Starvation. If a doodlebug has not eaten an ant within three time steps, at the end of the third time step, it dies of starvation and is removed from the grid. Breed. If a doodlebug survives for at least eight time steps, at the end of the eighth time step it spawns off a new doodlebug in the same manner as an ant. If no adjacent cell is empty, no breeding occurs. Once an offspring is produced, a doodlebug cannot produce another offspring until it has survived eight additional steps. Starvation takes precedence over breeding; that is, a starving doodlebug cannot breed. During each time step, the doodlebugs act before the ants. That is, a doodlebug may eat an ant that was about to move and possibly to breed; as a result, that ant is dead and can no longer do either. If an organism (i.e., an ant or a doodlebug) is eligible to breed but prevented from doing so by virtue of no empty adjacent cells, it remains eligible to breed on the next step. This Assignment Write a program to implement this simulation and draw the world using the ordinary characters ‘o’ and ‘x’ representing ants and doodlebugs, respectively. Create an abstract class called Organism that encapsulates basic data common to ants and doodlebugs. This class should have a virtual function called move() that is defined in the derived classes Ant and Doodlebug. You will also need a representation of the grid itself, and each cell of the grid should contain the null pointer (if empty) or a pointer to an Organism. Program Arguments The command line to run your program should resemble the following, where each of the arguments is an integer, and where any of the arguments (plus the following ones) may be defaulted:– ./PA6 gridSize #doodlebugs #ants #time_steps seed pause 1. gridSize — an integer representing the number of cells along one dimension of the grid (defaulting to 20) 2. #doodlebugs — an integer indicating the number of doodlebugs (default 5) 3. #ants — an integer indicating the number of ants (default 100) 4. #time_steps — the number of time steps to play (default 1000)
2 This would be highly unusual, because the cell from which the ant moved would now be vacant. 3 Obviously, if the ant cannot move, it also cannot breed, because there is no empty adjacent cell into which could be occupied by the newly born ant.
Programming Assignment #6 3 March 2, 2017
5. seed — an integer indicating the seed for the random number generator, with zero meaning to use the current time as the seed (default 1) 6. pause — an indication as to whether to pause. Blank or zero means do not pause. A nonnegative value n means pause and print the grid after each nth step. Wait for one character input before continuing. You may represent your grid in any way that you choose. For example, it may be two-dimension array similar to the ones we created for the Game of Life, or it may be an array of pointers to vectors, or it may be some other two dimensional data structure that is easy to access by indexes in the x and y directions. Each element of the grid should be an Organism * — i.e., a pointer to an object of type Organism. Before the start, the specified number of Ants and Doodlebugs should be placed on the board at random locations. Termination The simulation should terminate after the number of steps specified on the command line or when all of the ants or doodlebugs are gone. After termination, print to cout a summary of the simulation, including the original command line as represented by argv, the number of steps simulated, the total number of ants during the course of the simulation and the number remaining,3F4 the total number of doodlebugs in the course of the simulation and the number remaining, and a picture of the final grid. Deliverables You should create this project as a “makefile project with existing code” in Eclipse CDT as described in Lab #2.4F5 When you are ready to submit, clean the project and then Export it to a zip file, also as described in Lab #2. The zip file should be named PA6_username or PA6_teamName, where username is replaced by your WPI login identifier, and where teamName is the name of the team as assigned in Canvas. The zip file should contain the following:– All of the C++ files of your project, including your .cpp and .h files of your base and derived classes, plus at least one .cpp file for your main() function and simulation control. A makefile. The target name should be PA6. The makefile must be such that the graders can use it to build your project outside of Eclipse.5F6 The output of at least two different test cases. You must also submit a document called README.txt, README.pdf, README.doc, or README.docx summarizing your program and its principal classes and methods, how to run it, and detailing any problems that you had. If you borrowed any part of the algorithm or any test case for this assignment, be sure to cite your sources. Your README file should not be part of the zip file. 4 By “total number” in these two bullets, we mean the number of ants or doodlebugs at the start of the simulation plus the number of successful births. 5 The easiest way to do this is to replace the Lab 2 files with your own and then edit the Lab 2 makefile to refer to the names of the .c and .h files of this project. 6 This happens automatically if you create the project and export it exactly as specified in Lab 2. However, it is worth checking to make sure.
Programming Assignment #6 4 March 2, 2017
Before submitting your assignment, execute make clean to get rid of extraneous files, including Debug directories. Submit to Canvas under this assignment, which is named PA6 — Polymorphism. Programs submitted after 6:00 pm on due date (March 2, 2017) will be tagged as late. Since this is the end of the term, no there can be no forgiveness for late assignments. Grading This assignment is worth fifty (50) points. Your program must compile without errors in order to receive any credit. The abstract organism class – 5 points:– Correct definition of class and virtual methods – 5 points The ant subclass – 9 points:– Correct definition of subclass – 3 points Correct implementation of move() function – 3 points Correct implementation of breeding – 3 points The doodlebug subclass – 12 points:– Correct definition of subclass – 3 points Correct implementation of move() function – 3 points Correct implementation of breeding – 3 points Correct implementation of eating – 3 points Simulation framework – 15 points:– Grid implementation – 5 points Primary simulation loop invoking the move() methods of organisms – 5 points Processing command line arguments and setting up initial configuration – 3 Satisfactory output of steps of the simulation – 2 points Satisfactory README file explaining your class and your testing and showing the output of all test cases – 5 points Satisfactory execution of graders’ test cases – 4 points Penalty of ten points if your project is not clean before creating the zip file or for submitting your programs in something other than a zip file. If the graders cannot build your program by executing make in a Linux command shell, your grade will be zero. There will not be an opportunity to fix it before the end of the term.
It is therefore in your interest to be doubly sure that your program compiles correctly. The best way to do this is to build and run it exactly as the graders will — i.e., download the image as submitted to Canvas, unzip it to an empty directory outside your normal directory hierarchy, type the make command, and then run the program with a suitable command line, preferably one that you reported in your README file
