EECS 280 Tutorials

Style Checking

This tutorial will show you how to run style checking tools on your source code.

Style criteria

First, take a look at the EECS 280 C++ style guide.

We will use several tools to check the style of your code.

oclint checks

• Lines are no longer than 90 characters.
• Functions are short.
• Code is not too deeply nested.
• Functions do not have too many parameters. (Structs or classes should be used for functions that require more inputs).

cpd checks for significant code duplication.

Prerequisites

You can connect to CAEN Linux, where the tools are installed. See the CAEN Linux tutorial for help.

$ ssh awdeorio@login.engin.umich.edu
...
Success. Logging you in...

You have some source code you want to check. Our example contains a long line.

#include <iostream>
using namespace std;

int main() {
  // primer-spec-highlight-start
  cout << "hello world this is a veryyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy long line" << endl;
  // primer-spec-highlight-end
}

Make sure the code compiles before running style checks. If you have a Makefile, you could just type make.

$ g++ test.cpp -o test

Check style manually

Run oclint on test.cpp. You’ll need to load a module on CAEN, which adds a tool that isn’t available in the standard environment. There’s a long line in our example, which results in error output.

$ hostname
caen-vnc-vm16.engin.umich.edu
$ module load oclint
$ oclint \
    -rule=LongLine \
    -rule=HighNcssMethod \
    -rule=DeepNestedBlock \
    -rule=TooManyParameters \
    -rc=LONG_LINE=90 \
    -rc=NCSS_METHOD=40 \
    -rc=NESTED_BLOCK_DEPTH=4 \
    -rc=TOO_MANY_PARAMETERS=4 \
    -max-priority-1 0 \
    -max-priority-2 0 \
    -max-priority-3 0 \
    test.cpp \
    -- -xc++ --std=c++17

OCLint Report

Summary: TotalFiles=1 FilesWithViolations=1 P1=0 P2=0 P3=1

/home/awdeorio/test.cpp:6:1: long line [size|P3] Line with 104 characters exceeds limit of 90

[OCLint (https://oclint.org) v22.02]

oclint: error: violations exceed threshold
P1=0[0] P2=0[0] P3=1[0]

Run cpd on test.cpp. You’ll need to load the pmd module, which contains cpd. There isn’t any duplicate code in our example, so there is no error output.

$ hostname
caen-vnc-vm16.engin.umich.edu
$ module load pmd
$ cpd \
    --minimum-tokens 100 \
    --language cpp \
    --failOnViolation true \
    --files test.cpp
Added /afs/umich.edu/user/a/w/awdeorio/test.cpp

Check style automatically

You can run the style checks using the Makefile on an EECS 280 project.

Copy code to CAEN Linux

We’re going to synchronize our code to CAEN Linux many times. These shortcuts will let you synchronize quickly and easily.

Be sure that you can avoid repeated two-factor authentication (2FA). In a separate terminal, connect to CAEN Linux with SSH so you won’t have to enter your password again.

$ ssh awdeorio@login.engin.umich.edu
Password:
Duo two-factor login for awdeorio

Enter a passcode or select one of the following options:

 1. Duo Push to XXX-XXX-3142
 2. Phone call to XXX-XXX-3142
 3. SMS passcodes to XXX-XXX-3142

Passcode or option (1-3): 1
Success. Logging you in...

$

If you didn’t already, add a make sync shortcut to your Makefile.

Clean up (from your laptop).

$ hostname
manzana.local
$ pwd
/Users/awdeorio/src/eecs280/p1-stats
$ make clean

Copy (from your laptop).

$ hostname
manzana.local
$ pwd
/Users/awdeorio/src/eecs280/p1-stats
$ make sync
rsync -rtv --delete --exclude '.git*' --filter=':- .gitignore' ./  awdeorio@login.engin.umich.edu:p1-stats-copy/

Connect to CAEN Linux

Connect to CAEN Linux via ssh. If you’re already connected, you don’t need to connect again.

$ hostname
manzana.local
$ ssh awdeorio@login.engin.umich.edu
Success. Logging you in...
...
$ hostname
caen-vnc-vm16.engin.umich.edu

Change directory to the folder containing your source code. In this tutorial, we’re going to use the copy created by rsync via make sync. Note that you might also have a p1-stats directory created during the Version control on CAEN Linux tutorial.

$ pwd
/home/awdeorio
$ ls
p1-stats p1-stats-copy
$ cd p1-stats-copy
$ pwd
/home/awdeorio/p1-stats-copy

Run style checks

We’ve provided a make style Makefile target to run all the style checks for you.

$ hostname
caen-vnc-vm16.engin.umich.edu
$ pwd
/home/awdeorio/p1-stats-copy
$ make style
...
EECS 280 style checks PASS

Acknowledgments

Original document written by Andrew DeOrio awdeorio@umich.edu.

This document is licensed under a Creative Commons Attribution-NonCommercial 4.0 License. You’re free to copy and share this document, but not to sell it. You may not share source code provided with this document.