Homework Setup

Start on May 19, 2025

Due on May 26, 2025

Setup on Coursys

Find a group to work with for the homework assignments and the final course project. The group size is 3 people or less. We will be checking that all group members are contributing equally to the homework submission and the final project.

Along with your group members, register yourself as part of a group on Coursys.

Create a memorable name for your group. If you need help, seek help. Make sure there is no whitespace in your group name or anything that might cause a mojibake (please use plain ascii). Please use an underscore to join together words instead of hyphens.

Important: Do not use any obscene words in your group name. Be mature about your choice of group name. That does not mean it cannot be funny, just be aware that your choice of group name may offend someone else so be considerate of others.

Go to the Course Discussion Page and select [Activity Digest]. Change the Digest Email Frequency: to a setting that send you email notifications, like so:

Setup Git Repository

Git Basics

In this course, your programs will be managed and archived using Git. The basic idea is as follows:

• Every student and group gets a private storage area called a repository on the SFU server machines, or “repo” for short.
• Your code is stored in your repo. Every time you make a change to your code, you commit a new revision of your code to the repo for permanent storage. All revisions you ever commit are kept, and you can retrieve any committed revision any time. This means you have a combined backup and means to undo any changes you ever make. This is how software engineers manage their code projects.

Create new repository on SFU Github Enterprise

Decide in your group the person that will create the repository on SFU Github Enterprise and invite the other group members as a Developer with write/admin permissions. The main maintainer in the group should follow the instructions in this section.

Go to SFU Github Enterprise and log in with your SFU username and password, the same one you use to check your e-mail on the SFU Outlook mail server. You should enable 2FA if you have not done so already and also go through the 2FA authentication.

Once logged in, you will see a list of your existing repos if you have created any in the past. Create a new Private repository for this class by clicking the New Repository button (if this is your first repository on SFU Github) or the New button to create a new repository for the homework assignments for this course.

On the Create a new repository page, select a Repository name. You must name your repo: CMPT379-1254-g-GROUP where GROUP is the group you registered on Coursys (see above). For example, a repository name might be CMPT379-1254-g-ethicsgradient. Make sure you add the g- before your group name. It is important to name the repo exactly as you see here.

Write an optional Description.

Important: You must choose this repository to be Private. We will not accept any repository for the homeworks in this course that is marked as Public. Your repo must be visible only to yourself and your group members. You must not give access to your repo to any other students except your group members, the TA(s) and the instructor..

Plagiarism is a serious academic offense.

At any point in the future you are also not allowed to either mark this repository as Public or copy the code to a different public repository (on Github or elsewhere).

The other initialization choices are optional (there is more about setting up your .gitignore file below).

Then click on the Create repository button.

Your repo has now been created. You will be taken to the web page for your newly created repo.

Add the instructor and TA as Developers

This is the most important step in the setup of your GitHub repository

The course instructor and the TAs need access to your repo in order to test and grade your code. Add the instructor and TAs as a member of your repo by clicking on the Settings menu and choosing Add People which looks like this:

On the page that loads up type in (or individually copy/paste) each of the following list of names: anoop,mam47,sba236,yha274@sfu.ca,and invite them as a Collaborator.

Set up notifications

You should be automatically set up to “Watch” changes to your repository, but ensure that you are watching changes.

Set up your notifications by going to your personal settings accessed through your user icon on the upper right corner:

Then select Notifications (with the bell icon) and make sure you are notified about changes to the repository:

Make sure you are notified about Github Issues.

Setup SSH Key

Next we will set up the Secure Shell (ssh) keys so you can access your repo without a password. If you do not already have an SSH key then first generate a new ssh key.

If you have set up your SSH key correctly then you will have a public key. View it

cat ~/.ssh/id_*.pub

Then add your public SSH key to the GitHub server using these instructions. .

Clone your Repository

Download a copy of your repo to your CSIL machine. The action of making a local copy of your online repo is known as a “clone”.

In the terminal window, enter the commands

git config --global user.name USER
git config --global user.email USER@sfu.ca
git config --global core.editor nano         # or set it to your favourite editor
git config --global push.default current
cd $HOME
git clone git@github.sfu.ca:GROUPUSER/CMPT379-1254-g-GROUP.git

where USER is your SFU username, GROUPUSER is the SFU username of the person who created the group repository and GROUP is the name of the group you have already setup on Coursys. If you skipped any of the above steps in setting up your GitHub repo this command will not work. The system might prompt you for a username/password combo. Supply the usual answers. To avoid entering your username/password over and over again you can set up passwordless ssh.

Your repo will be cloned into a new directory (also known as a folder) called CMPT379-1254-g-GROUP.

Create your Homework 0 directory

After cloning your repository, make sure you are inside your repository and at the top level. Create a directory for Homework 0:

mkdir hw0
cd hw0
pwd

When you print your working directory it should look like this:

CMPT379-1254-g-GROUP/hw0

Add a file README.md to this directory using your favourite editor and then git add README.md and git commit -m "Initial hw0 commit" and then git push to send your new directory and file to the GitHub server. Open up GitHub on a web browser to check that you can see hw0/README.md in your repository on the web browser.

Add a .gitignore file at the top level of your git repository to avoid committing and pushing useless files to the GitHub server. Here is a typical .gitignore file for C++ projects.

# Compiled Object files
*.slo
*.lo
*.o
*.obj

# Compiled Dynamic libraries
*.so
*.dylib
*.dll

# Compiled Static libraries
*.lai
*.la
*.a
*.lib

Getting homework files

You must have git and python (3.x) on your system to run the assignments. Once you’ve confirmed this, run this command:

git clone https://github.com/anoopsarkar/compilers-class-hw.git

In the rmprefix directory you will find various python programs which you will use to test your solution to this homework and to prepare files you will upload to Coursys.

You will get updates to the homework files by going to the directory where you cloned the repository and then doing:

# go to the directory where you did a git clone
git pull origin master

Before you start a new homework make sure you do a git pull to get the latest homework files.

To get started with your homework do the following steps.

Copy over files

Clone your git repository and enter that directory and copy over the files:

git clone git@github.sfu.ca:GROUPUSER/CMPT379-1254-g-GROUP.git
cd CMPT379-1254-g-GROUP
mkdir -p rmprefix
cd rmprefix
cp -r /your-path-to/compilers-class-hw/rmprefix/* .
git add *
git commit -m 'initial commit'
git push

If you update my repository using git pull then you might have to copy over the new files into your repository. Be careful you do not clobber your own files in the answer directory.

Default solution

Your solution must be compiled in the answer directory and must be called rmprefix. There is an incomplete solution to this homework in answer/default.cc. Copy it over as your initial solution:

cd CMPT379-1254-g-GROUP/rmprefix/answer
cp default.cc rmprefix.cc
make rmprefix

The Challenge

The objective of this homework is to lay out the development and testing methodology for the rest of the homeworks so it is designed to be a trivial task that can be tested.

Your task for this homework is to write a very simple C++ program that trims the leading whitespace (if any) from each line read from the standard input stream std:cin. Any other whitespace should be left untouched. For this homework we define whitespace to be only the ASCII space ' ' and tab '\t' characters.

For example, for the following input:

  line1
       line2
            line3

The output on standard output std::cout should be:

line1
line2
line3

Make sure only leading whitespace is removed. Any other whitespace should be preserved in the output.

Your Task

Write a C++ program called rmprefix.cc that does the task that is described above and add it to your git repository in the answer directory.

If your program succeeds you should exit from your program using exit(EXIT_SUCCESS). In this homework this should not happen but if your program exits with an error you should exit using exit(EXIT_FAILURE). The definitions of EXIT_SUCCESS and EXIT_FAILURE are in cstdlib (for C++) and in stdlib.h (for C).

Development and upload procedure

Remember to push your solution source code to your git repository:

cd CMPT379-1254-g-GROUP/rmprefix/answer
git add rmprefix.cc
git commit -m 'initial solution'
git push

Then each time you finish a component of your solution you can push it to the remote repository:

git add answer/rmprefix.cc # or other files you worked on
git commit -m 'commit message'
git push

You have been given three helper programs to help you develop your solution to this homework.

Run your solution on testcases

Run your solution program on the testcases using the Python program zipout.py. Your solution must be compiled in the answer directory and must be called rmprefix. Run against all testcases as follows:

# go to the directory with the file zipout.py
python3 zipout.py

This creates a directory called output and a file output.zip which can be checked against the reference output files (see section on Check your solution below).

If you run zipout.py multiple times it will overwrite your output directory and zip file which should be fine most of the time (but be careful).

For this homework the program zipout.py uses the binary answer/rmprefix by default. To discover the command line options for this program, run:

python3 zipout.py -h

The option to log verbose debugging information to a log file will be very useful in future homeworks to debug your own code.

Check your solution

Check your solution accuracy using the Python program check.py. You must create an output.zip file using the above step in Run your solution on testcases. Note that the references are only available for the dev testcases. When you are graded you will be evaluated on both the dev and test testcases. output.zip contains your output for both sets of testcases.

python3 check.py
Correct(dev): 4 / 6
Score(dev): 4.00
Total Score: 4.00

Package your output and source for Coursys

You must upload your output zipfile and source code to Coursys. You should prepare your source for upload using the Python program zipsrc.py.

# go to the directory with the file zipsrc.py
python3 zipsrc.py

This will create a zip file called source.zip. You should upload this file as your submission to hw0 on Coursys.

Be careful: zipsrc.py will only package files in the answer directory. Make sure you have put all your supporting files in that directory. In particular, put relevant documentation into answer/README.md.

If you add any testcases of your own please put them in the directories answer/testcases/[your-username]/ and answer/references/[your-username]/ using the same convention used by zipout.py and check.py.

Ground Rules

• You must turn in two things:
  • Your source code from the answer directory as a zip file source.zip produced by running python3 zipsrc.py must be uploaded to the hw0 submission page on Coursys.
  • Your output on the testcases which is the file output.zip produced by running python3 zipout.py must be uploaded to the hw0 submission page on Coursys. When we run check.py on the public testcases it should have a value higher than the output from the default.cc program to get any marks.
• Your source code from source.zip must be in your git repository. Please commit and push often in order to get feedback on your code.
• You cannot use data or code resources outside of what is provided to you. If you use external code snippets provide citations in the answer/README.md file.
• For future homeworks, for the written description of your solution and supporting documentation, you can use plain ASCII but for math equations it is better to use kramdown. Do not use any proprietary or binary file formats such as Microsoft Word.

If you have any questions or you’re confused about anything, just ask.