Program Design and Testing Implementing Langton’s Ant Goals Review of programming with arrays Convert requirements (i.e. the rules) to a software design Think about the testing process, before and after writing the program. You will design, implement, and test a program that implements a simulation of Langton’s Ant. For a brief explanation consider Wikipedia: https://en.wikipedia.org/wiki/Langton%27s_ant (Links to an external site.). Note that it can be considered as a cellular automaton. This means that you have an array or matrix of cells. Each turn or step, the value of each cell may change based upon a simple rule. For the Ant there are two simple rules. The rules are: In a white square, turn right 90o and change the square to black. In a black square, turn left 90o and change the square to white. You should use a blank character for a white space, and use the number sign “#†for the black space. And for the Ant? “@” works fine. (You can use other sign as long as it is easy to see.) Left ? Right? Those are relative directions! How are you going to keep track of the direction the Ant is facing? How will you “remember†what color the current cell occupied by the Ant is or was? You will create an Ant class to help organize, hold, and manipulate this information. Your program will prompt the user to enter the number of rows and columns for the 2D array. You should also prompt the user for the number of steps. If you want to limit the size of the board or number of steps, suggest values to the user. (You are suggested to choose a size that is no larger than the default width 80 when you are developing). Your program should display each step by printing out the whole board. Use functional decomposition to develop functions to validate the input. (You can make a validation class if you would like.) You should start by asking the user for the starting location of the Ant. For testing purposes, always start the Ant at the same location. Then try different locations. Remember that when you create the array dynamically, you need to de-allocate the space to avoid memory leaks. You can use valgrind to check for memory leaks. Then what if the ant meets a wall collision (i.e. ant attempts to step out of the bounds of the array)? Think about the corner case. For example, the ant makes it to the edge of the game board, and according to the rule, it needs to make a turn and end up getting out of the game board. It is your design decision, and make sure it is properly handled. Previously, students tried different actions, such as “skip the step forward step, make another turn and then continue onâ€, or “wrap the board around so that the ant will appear on the other sideâ€, or “turn the ant around and send it back onto the boardâ€. As long as it makes sense, you are fine. But do not terminate the game before it reaches the designated step. In this project, you are asked to implement a menu function that can be reused in later programs. A menu function is something that is printed to the screen that gives the user options, as if you were using a DVD menu, or a video game menu. It should then verify the user’s input and return something to tell the rest of the program what the user chose. For example: 1) Start program 2) Do task 1 3) Do task 2 4) Do task 3 5) Play again 6) Quit It can be used in future programs by having it be easily changeable to whatever program you are writing. If you want to write a menu class instead of a menu function, that is totally fine as well. You will create your design document BEFORE you start coding and include that in your reflections. Simply stated, program design is identifying the problem to be solved, identify the inputs, specify the desired output, and then develop the algorithm(s) to convert the input into the output. In your reflections document, you should also explain how you have to change the design because your first idea didn’t work. Explain what you learned during this project. The TA will grade on how well your implementation matches your design. Note: There are a lot of details that are not determined in this requirement. They are left for you to decide, as long as your program meets the required rules in the grading part. For more questions, ask your grading TA for clarification or post it on Piazza. Extra Credit (5%): Add the option for the user to have a random starting location of the Ant. If you have this option, you must tell users at beginning and give instructions on how to choose this option. Otherwise, TA won’t test this function and give extra credit. What to submit: Your program files (.cpp .hpp). The reflections document (pdf). A makefile. If you do not provide a makefile it will not be graded. All the files must be submitted in a zip archive. GRADING Programming style and documentation: 10% Build the board 2D array: 10% Input validation function(s): 10% Create the source and header files for the Ant class properly: 15% Displays each step correctly, including running for the correct number of steps: 10% The display allows the user to see the change(s) in the shape(s): 10% Allow the user to specify the starting location of the Ant: 10% Implement a menu function that can be reused in later programs: 15% Reflections document to include the design description, test plan, test results, and comments about how you resolved problems during the assignment: 10% IMPORTANT POINT: Keep in mind that this is a programming assignment. You are not writing a program to share with others for their enjoyment. Too often students forget this and the attempt to make it entertaining which also makes it more difficult, and has little to do with the grading. You are graded on developing the design, writing the code, and testing your program. You will use text-based output. It may not be pretty, but it will demonstrate your design and implementation works. If you have other programming experience and want to use something else, check with your grader before doing it.
