Lab 0 Due Wednesday Sep 11, 11:59pm ET

Introduction to Go

Resources

Lab 0 FAQ.

Overview

In this warm-up lab assignment, you will solve two short problems as a way to familiarize yourself with the Go programming language. We expect you to already have a basic knowledge of the language. If you’re starting from nothing, we highly recommend going through the Golang tour before you begin this lab.

Software

You can download the initial software from here.

We use Go’s package testing for automated testing. You will find the code in the same directory as this README. The two problems that you need to solve are in q1.go and q2.go. You should only add code to places that say TODO: implement me. Do not change any of the function signatures as our testing framework uses them.

Q1 - Top K words: The task is to find the K most common words in a given document. To exclude common words such as “a” and “the”, the user of your program should be able to specify the minimum character threshold for a word. Word matching is case insensitive and punctuation should be removed. You can find more details on what qualifies as a word in the comments in the code.

Q2 - Parallel sum: The task is to implement a function that sums a list of numbers in a file in parallel. For this problem you are required to use goroutines (the go keyword) and channels to pass messages across the goroutines. While it is possible to just sum all the numbers sequentially, the point of this problem is to familiarize yourself with the synchronization mechanisms in Go.

Testing

Our grading uses the tests in q1_test.go and q2_test.go provided to you. To test the correctness of your code, run the following:

% cd labs/lab0
% go test

If all tests pass, you should see the following output:

% go test
PASS
ok	/path/to/lab0  0.009s

To run a single test (e.g., Test1), run the following:

% go test -run Test1
--- FAIL: Test1 (0.00s)
    q2_test.go:11: Sum of q2_test1.txt failed: got 0, expected 499500

FAIL
exit status 1
FAIL	intro-go	0.001s

Apparently, the above test fails due to a certain reason. It is your job to finish the implementation and pass the test.

Please post questions on Ed.

Point distribution

Your code will be tested on Autolab. No marks will be awarded if your code does not pass the test. You will receive full marks only if your code successfully passes the test.

What (and how) to hand in

Submitting on Autolab

You must turn in your lab assignment using Autolab. Read this document for instructions on how to sign up for Autolab. If you did not receive a confirmation email from Autolab to set a password, enter your @virginia.edu email, and click “Forgot your password” to get a new password.

NOTE: Do not use your UVA email aliases to sign-up for Autolab.

Create a tar file that contains the two Go source files only, q1.go and q2.go (you should use the extension name .tar, not .tgz, nor .7z/.zip) and name your tar file as lab0-handin.tar. When you upload your assignment, Autolab will automatically untar it and test it. You should verify that the result that Autolab generates is what you expect. Test your code on Zeus before submitting it to Autolab. Your code is tested in a cloud Linux VM. Assignments that do not compile or run will receive a maximum of 50%. Note that we have provided ample resources for you to verify that our view of your assignment is the same as your own: you will see the result of the test execution for your assignment when you submit it.

You can resubmit your lab an unlimited number of times before the deadline. Note the late submission policy: labs will be accepted up until 3 days past the deadline at a penalty of 10% per late day; after 3 days, no late submissions will be accepted, no exceptions.

Submitting on Canvas

Please also submit your tar file on Canvas. The submission should include the two Go source files, g1.go and q2.go, and this is justfor the GTAs’ record.

NOTE: Canvas submission will remain open after the due date, but we will not use Canvas submission timestamp. Instead, we will use the timestamp of your last Autolab submission for late penalty.