HW1: Mark your pointers carefully

This assignment is on a frequency analysis of Mark Twain’s texts. The main CS objective is to understand
how to code and use linked lists.

Assignment details

Here are the relevant files and directories.

hw_twain.pdf: The file contains a description of the assignment. You can click on the file in the left pane to open it in your browser. Please read it carefully!

Twain/: This folder contains the files for your submission. You must write your code in this folder. Do not put code in a subfolder. Your Makefile
must be in this directory, and should create the executable “twain” in this directory. Here is a description of files
within this directory.

• twain-cleaned.txt: This file has all of Mark Twain’s writings, cleaned up. Each line has a separate word, all in lowercase.
  Moreover, all words of length less than six have been removed.
• simple-input.txt, simple-output.txt: These are test input files, to check your code. Please leave these files in this directory.
  The checking script with check whether your output (for simple-input.txt) matches this output.
• Tests/more-input.txt, Tests/more-output.txt: These are more test I/O files that are comprehensive. First try to get your code to
  work on simple-input.txt, before testing with these files.
• The Tests/ folder contains an extra copy of simple-input.txt, simple-output.txt, and twain-cleaned.txt, if you accidentally overwrite them.

Do not delete any of files in the Tests directory!

checkcode.sh: This is very important! This is a script to do some basic checks on your solution. You can run it as “./checkcode.sh”, in terminal (while you’re in the workspace folder). I recommend that you keep a separate terminal open, where you only run this command. The command produces console output that explains the checks. If it finally ends with “PASS”, this means your solution passed the tests. This does not guarantee that your code is correct, or that you will get any points. But if your code does not pass the test, you will not get any points when you submit. To ensure that the scripts runs properly, it is best to delete your executable and object files (*.o) files from the Twain/ directory. This ensures that this script will regenerate the executable, to check for any errors in compiling. Ideally, you should define a “clean” rule, so that the command “make clean” deletes the object and executable files. A common error is to overwrite the simple-input.txt and simple-output.txt files. Before running ./checkcode.sh, you may want to first get a fresh copy from the Tests/ directory.

README.md: That is the file you’re reading right now 🙂 You can click on this file, to get a tab with this. Again, keep this open for your convenience.

RoboGrader/: This has my checking and testing scripts. Do not modify anything here!

Coding

Ideally, you should code directly through the command line, using an editor like vi or vim. Alternately, you can upload files directly. Go to the File menu, and click on “Upload”. But pleae compile your codes through the command line, and make sure everything runs in the Codio box. There is no guarantee that code compiled on your machine works on the Codio box (often, because of incompatible OSes or text editors introducing strange symbols, etc.) We will be testing your code directly in the Codio box, so ensure that you compile codes here. Please use the checkcode.sh script to ensure everything is running. A significant part of grading is automated, so it is essential that you follow these rules.

Even if you’re not familiar with Unix, I highly recommend sticking to the command line. You will get better at it, and it will help you greatly in the long run.

Formally, Codio is providing a “container” (similar to a virtual machine), which provides the illusion of a full fledged operating system. From your standpoint, think of each Codio box (for every assignment) as a fresh computer, provided just for that assignment. The different Codio boxes are completely independent of each other. Only you and me (the instructor) has access to this machine. In reality, each of these boxes is hosted in the cloud.

How grading works

After the deadline, an autograde script is run on the container. On running the autograde script (which is in a secure directory hidden from the student), there is a new directory called TwainStudent that is created. All relevant source files are copied from the Twain/ directory to the TwainStudent/ directory. This is to ensure that the autograder does a fresh compile only using C/C++ code files. There is a copy of the RoboGrader code inside the secure directory, with everything set up to run on the TwainStudent/ directory. The autograde will create a log file “TwainStudent.log”, which gives the score and explains a failed test (if any). RoboGrader will also copy the file with the erroneous tests case and the erroneous output. The log file gives the correct output for the erroneous line only.