Welcome to SIGSoft

Chairs: ◦ Drew Cross◦ Eric Parsons

Treasurer: ◦ Dylan Nugent

“Authorized Agents”: ◦ Ciara Proctor◦ Sean Nicolay

What SIGSoft was like last year. What to expect from us this year.

◦ Side note: Our meetings will become much more informal over time

Who are we?

Permanent Room TBA via newsgroup eventually…

Today: “Random” examples of bad code Next week: Possibly a GIT tutorial Survey results

Announcements

As of 12pm Tuesday

What do you think about this?

This is a misuse of white space In this example, the --> is a combination of

the decrement operator (--) and the greater than operator (>).

Note: the -> operator does exist in C/C++

There is no --> operator

Now what do you think?

On the previous slide, a while loop is performing an action typically performed by a for loop.

By switching to a for loop, the comparison and the decrement operation are isolated. This separation helps make the code easier to understand.

Use appropriate control structures

Two examples of scope brace placement

Either is fine, just be consistent

I prefer the latter because of screen real estate and putting the opening brace on a new line does not convey new information to me.

On the previous slide I showed two examples of curly brace place placement. Either is fine if you are consistent about your usage.

This point is moot in Python as it uses whitespace (indentation) for indicating scope.

If you join a project and everyone is following a coding convention (variable names, indentation, etc) conform to their convention; don’t try to change conventions mid-project unless there is a really good reason to.

Coding conventions

Managing Complexity"Everyone knows that debugging is twice as hard as writing a program in the first place. So if you’re as clever as you can be when you write it, how will you ever debug it?”

--Brian Kernighan

The human brain can only handle so many tasks at once. (about 7)

Always strive for simplicity and clarity when designing your programs and when choosing names for classes, methods/ functions, and variables.

Write simple/clear code first and profile it. Only then perform optimizations.◦ “…premature optimization is the root of all evil.” –Donald Knuth

Key Point

From Code Complete: Second Edition (pg 260)

What is this java code doing?

Don’t be afraid to write longer names if needed (but be concise!) For example: numStudents is better than numberOfStudentsInTheClass Learn the AutoComplete shortcuts for your editor

◦ Vim: Ctrl-n Eclipse: Ctrl-Space, or Cmd-Space on Mac

Now with sane names…

Bad variable names: myInt, arr, thing1, returnVal, input, output, result, a, b, c

Short names can be ok but think before using them. ◦ i.e. x,y,z for Cartesian coordinate system i,j,k for loop control

I can’t stress the power of good names enough!Which is why the next talk I (Eric) do will be on naming conventions.

A more real-world example…

Hint: these are all different files and I could have picked any one of about 200 others for this example…

What is wrong here?(Aside from the fact that PHP is being mixed with HTML)

In the previous slide, the PHP/HTML that generates the site’s overall layout is duplicated via copy/paste in a couple hundred files.◦ If you wanted to make a site wide change you would

have to either: Hope the relevant file was an include that all the pages used Go through every file making your changes to each Re-write the site to eliminate the repetition and separate

logic from presentation

As a result, this site is inflexible and making changes is difficult and tedious

Repetition

If you find yourself wanting to violate DRY by copy-pasting code, refactor instead

Benefits of not repeating code◦ Single place for change◦ Can give a name to the set of operations being performed (Reducing complexity)

Also: Don’t reinvent the wheel. Chances are that someone has had to solve the problem you are now facing. Maybe that solution uses a software license compatible with your code.

DRY (Don’t Repeat Yourself)

The GIT version control system

Next Talk

Engineering Open House (EOH)◦ Will be held March 9-10, 2012

Sample Ideas: (Feel free to use them if you are stuck)◦ Where are my classes? http://goo.gl/jQZ0e◦ Hex Game w/AI opponent

http://en.wikipedia.org/wiki/Hex_(board_game)◦ Import class schedule into Google Calendar◦ Continue working on IdeaMine

Projects

Break into groups based on interest Work on just coming up with an idea or

problem statement for now◦ However, if your group is set on an idea, let me

know Repository access

Share contact info◦ You can post to the newsgroup (please do) but if

you have a set of specific people that you want to contact, please try to email each other.

Projects