PA0

Table of contents

  1. Learning Goals
  2. Getting Help
  3. Getting Started
    1. Connecting to ieng6
    2. Downloading the starter code
    3. Compiling and running the starter code
  4. Your Task
  5. Writing variables.c
    1. Compiling and running variables.c
  6. Submission
    1. Downloading variables.c to your local machine

PA0 will not have an effect on your final grade in CSE29, but it’s still a worthwhile exercise to help accustom you to how we’ll write code in this class!

Learning Goals

Welcome to your first PA for CSE 29!

In this assignment, we will:

  • Learn how to write a C program that follows a given specification.
  • Practice sshing to ieng6 machines and using vim and gcc to write, compile, and run C programs.

We expect everyone to have experience with programming in a high-level language like Java or Python. If this isn’t the case for you, please reach out to staff as soon as possible!

Another important note: unless you have prior experience with C and the command line, we recommend waiting until after Lab 1 to start working on this PA, as Lab 1 will cover the necessary tools and concepts to complete this assignment.

Getting Help

You are always welcome to come to either instructor or TA office hours. Both of which are listed on the course website. In office hours, however, conceptual questions will be prioritized.

As with all other PAs, you are highly encouraged to collaborate with your peers. Study Groups and Edstem are great places to get started doing this. :)

Getting Started

Connecting to ieng6

As shown in Lab 1, you should use the ssh command to connect to an ieng6 machine.

Once you’ve connected, it would be a valuable exercise to poke around using the commands covered in Lab 1 to get a better feel for the terminal. Try pwd to see where you are.

$ pwd
/home/<your-username>

Downloading the starter code

From here, let’s create a new folder in our home directory called pa0 to store the files for this PA:

$ mkdir pa0

From here, let’s navigate into the pa0 directory. We can use wget to download the starter code for this PA:

$ cd pa0
$ pwd
/home/<your-username>/pa0
$ wget https://cse29spring2026.github.io/assets/pas/pa0/variables.java

After you’ve run the command above, you should see variables.java in your current directory. You can use ls to check this:

$ ls
variables.java

And as in Lab 1, you can use vim to open the file and take a look at the code.

Compiling and running the starter code

This section will describe how to compile and run Java programs: we won’t be doing much more of this for the rest of this course!

To compile a Java program, you can run javac <program>.java. So in this case, you can run javac variables.java.

$ javac variables.java

If the above command runs without any output, then you’ve succeeded! If you ls again, you should see a new file called variables.class:

$ ls
variables.class  variables.java

Next, to run the program, you can run java <program>. So in this case, you can run java variables:

$ java variables
a = 10
b = 3
c = 2.5
a / b = 3
a % b = 1
a / c = 4.0
a / (int) c = 5
(int) (a / c) = 4
ASCII of A = 65
ASCII of a = 97

Your Task

Now, let’s move onto the actual task for this PA. Your task is to translate the variables.java program into a C program: variables.c.

Some things to keep in mind as you write your C program:

  • The output of your C program should match that of its Java counterpart. It’s recommended that you first go through these programs and try to execute them to get a better understanding.
  • You shouldn’t simply hard-code the output into your C program, you should faithfully reproduce the logic in the original Java code.

Writing variables.c

To write variables.c, let’s use vim to create and edit the file. You can run vim variables.c to get started.

The following C code snippet may be a helpful starting point for you to get started on variables.c:

#include <stdio.h>

int main() {
    printf("Hello world!\n");
    return 0;
}

Compiling and running variables.c

Once we’ve written a starting point for variables.c, we can use gcc to compile it. Exit vim and run the following command:

$ gcc variables.c -o variables -Wall

As with javac, if you don’t see any output after running gcc, then you’ve succeeded! You should see a new file called variables:

$ ls
variables  variables.c  variables.class variables.java

To run the program, you can type ./variables:

$ ./variables
Hello world!

Now, you can modify variables.c to match the logic of variables.java After each modification, you can re-run the gcc command to compile your code and then run it to check if your output matches that of variables.java.

You know you’re done when running variables.c produces the same output as variables.java!

Submission

For this PA, you will submit variables.c to Gradescope. (Submission link coming soon!)

Downloading variables.c to your local machine

On your ieng6 machine, you can use scp to download variables.c to your local machine.

Make sure that you’re running the scp command from your local machine’s terminal, not from the ieng6 terminal!

If you’ve set up your folders the same way as described in the “Getting Started” section, you can run the following command to download variables.c:

$ scp <your-username>@ieng6.ucsd.edu:/home/<your-username>/pa0/variables.c .

After you’re done, you should see variables.c in whatever directory you ran the above command from. Upload this file to Gradescope to submit your PA!

University of California San Diego. Built with Just the Docs.