Wednesday, April 12, 2017

Code Slow Finish Fast

Looking through student code today brought this quote to mind.

“I didn't have time to write a short letter, so I wrote a long one instead.” Mark Twain

Students are always in a hurry to write the code for programming projects. No matter how strongly I suggest they think about the problem and design their code most of them start coding right away. This often results is a lot of code where a small amount of code will work just as well if not better.

Often the techniques for less code require a bit more thought. Setting up a long set of if statements with a bunch of different variable names is tedious but doesn’t always require as much planning as setting up an array and loop solution does. Students are in a hurry so they take what they think are shortcuts.

Experience tells of course. My version of Whack A Mole (our current programming project) can be changed from 5 possible “moles” to 6 by changing one 5 to a 6. Some of my students would have to write, well let’s just say I don’t want to do the math.  We’ll go over the options during our next class. The theme will be to think more before starting to code though.

Tuesday, March 28, 2017

Math vs Programming

MathTake a look at these two equations. I found the first one on Facebook. The second is my first attempt at rewriting it for the computer. What is the answer?

Well the first answer is 1. The second answer is 9. How is that possible? If you think about it there is a sort of implied parenthesis around 1/3. It’s pretty clear in the more traditional mathematical expression that one is to divide by one third and not 1 divided by three. imageA more accurate expression for the computer would have some parenthesis to make things obvious. That would give one the answer 1 that the traditional expression provides.

We see this sort of thing a lot – students assuming that equations in programming are exactly the same as the mathematical expressions their are used to using.  The most common issue is students thinking that the = sign allows copies from left to right as well as right to left. After all in mathematics the = sign means that both sides of the equation have the same value. That is not the same think as the = sign meaning copy the value on the right into the location on the left.

Some functional languages do things differently. The WeScheme IDE and DrRacket used by Bootstrap for example. That curriculum takes a much more algebra focused look at computer science. Or is that a more computer science focus approach to algebra? Either way it seems to be very effective. (Note that Bootstrap training is available though CSPdWeek and other venues.)

Those of us using other platforms though have a lot to contend with as we teach students how to build expressions that mean what students think they mean. Is it worth the effort? I tend to think so. But it is confusing at times.  Days like to today make me rethink things.

Computer Science Teachers Association T-shirt Campaign

Are you a computer science education super hero? You know you are so now you need the t-shirt. Get yours here and also support the computer science teachers association. cs hero

Just the thing to wear to the CSTA conference or really any education event. I would love to see lots of them at ISTE to let people know that CS educators are there

Saturday, March 25, 2017

CSPdWeek: Free Professional Development for many K-12 Teachers

The people I talk to who went to last year;s event rave about it. If you are looking for some good professional development this is well worth looking into.

Thanks to funding from Infosys Foundation, NSF, NCWIT, and CSTA, CSPdWeek is *on* again for next year: July 17-21st, 2017

. CSPdWeek is a distinctive cross-curricular event that offers high-quality professional development for teachers planning to teach any of the following: 

  •       AP CS Principles
  •       AP CS A (Java)
  •       Exploring Computer Science
  •       Bootstrap

Each of these week-long workshops will be led by leaders in the field. In addition, counselors are invited to attend half the week (2.5 days) for professional development. 

Please share this email with anyone planning to teach computer science in K-12 during the 2017-18 academic year, as well as counselors at high schools. Extended details on each of the CSPdWeek tracks are below. Information and application materials are available at:

Colorado School of Mines is excited to host this exceptional event.

Thursday, March 23, 2017

ACM and CSTA Announce Cutler-Bell Prize Student Winners

Make no mistake I think the Cutler-Bell Prize is an outstanding award. I love that it recognizes early computer scientists (high school students!) for outstanding achievement.

This year's winners appear (based on the names) to be computational focused magnet schools. On one hand that such schools exist is great and even exciting. On the other hand I worry about the kids who have great interest in computer science but who don't get the opportunity to spend several high school years learning the cool stuff and working on great projects. Will the publicity for this award motivate more school districts to set up more similar magnet programs? Or perhaps at least look at expanding the CS offerings they offer? I hope so.

In the mean time I congratulate these students. It looks like they have done some serious work and I wish them great success in the future.

ACM and the Computer Science Teachers Association (CSTA) have announced the 2016-2017 winners of the Cutler-Bell Prize in High School Computing. Three high school students were selected from among a pool of graduating high school seniors throughout the US. Eligible students applied for the award by submitting a project/artifact that engages modern technology and computer science. A panel of judges selected the recipients based on the ingenuity, complexity, relevancy and originality of their projects.

The Cutler-Bell Prize promotes the field of computer science and empowers students to pursue computing challenges beyond the traditional classroom environment. In 2015, David Cutler and Gordon Bell established the award. Cutler is a software engineer, designer, and developer of several operating systems at Digital Equipment Corporation. Bell, an electrical engineer, is researcher emeritus at Microsoft Research.

The winners are Elizabeth Hu, Thomas Jefferson High School for Science and Technology (Virginia); Avi Swartz, Cherry Creek High School for Computational Biology (Colorado); and Aaron Walter, Yorkville High School for Computer Science (Illinois). Their submissions ranged from using data to study refugee migration models; determining type and quantity of protein components in biological samples; and a software program that evaluates students’ understanding of curriculum components.

Each Cutler-Bell Prize winner receives a $10,000 cash prize. This year’s recipients will be formally recognized at the Computer Science Teachers Association’s annual conference, July 8-11.

Tuesday, March 21, 2017

Datasets For Use in Teaching Computer Science

I found this thanks to the APCS A mailing list. 

CORGIS Datasets Project

The Collection of Really Great, Interesting, Situated Datasets

“The CORGIS Datasets Project seeks to make highly-motivating introductory computing experiences through simple, easy-to-pick-up datasets for beginners. We offer a wide range of libraries for many different programming languages and contexts. “

I haven’t looked at the libraries yet as they are for languages (Java, Python, and Racket) that I am not currently using but I would be if I were using them. There are also raw data sets in sql, JSON, and CSV formats. I use CSV files a lot and was very please with the look of the 43 data sets in that format. I can see some interesting projects ahead for my programming classes, data analysis in Advanced Placement Computer Science Principles, and even my freshmen course where we use EXCEL.

If you are interested in good data for real learning I recommend you take a look at

Friday, March 17, 2017

Hip Hip Array

My programming courses are a semester long. That’s it. After that someone else gets to teach them more programming and computer science. A semester is not a lot of time  so we can only cover so much material. There are days when I really envy my friends who have students for years as in 2, 3, or even 4 year long courses. On the other hand I am finding that I am appreciating the basics more and more all the time.

Take arrays for example. I’ve been around long enough and coded enough that I understand arrays pretty well. I’ve done the who pointer arithmetic thing in C. And the use of offsets in assembly language programming. So I understand what is behind arrays in ways I don’t have near enough time to explain to my students. I think this understanding gives me a greater appreciation for this tool in my toolbox. I literally spent an hour or so last night just contemplating the beauty and power of a simple array. Add to that the power of arrays of objects and mind blown.

OK maybe I get excited easily. On the other hand in many ways writing code seems as new and cool to me as it did when I tool my first programming course over 40 years ago. If anything I am developing new appreciation for the simple less complicated elements of programming languages.  One doesn’t need all the latest and greatest bells and whistles of languages and libraries to have fun writing code.

Though that doesn’t mean I am giving up features like Array.Sort. I’m not totally crazy.

Monday, March 13, 2017

March Madness and Programming Projects

Yesterday was selection Sunday and the NCAA announced the teams entering the 2017 basketball championships. So of course I thought about programming projects. I mean there is data and something a lot of my students are interested in so it is a natural. Now there are already all sorts of automated bracket generating tools on the Internet. LOTS of them. But being me I needed my own.

The first thing I did was build a data file. (NCAA 2017 seeding information) That link gets the comma separated data file. It looks in part like this:


It’s pretty basic with the seeding number, the university name and for most of them their record. Once I had that I could write a program to read in the data and display it. My next step was to write code to semi randomly (its weighted by seeding) pick which team went to each next step of the competition. I get graphic so I generated the following:


I’m thinking I could let students do something more simple in output. I did this with parallel arrays but I can see creating a class making some things easier. In any case I get to p[lay with reading and parsing data, building and processing arrays, and other data manipulation. There are many variations I could do here.

Students could create their own schemes for generating brackets. Or they could write code that lets the user select which teams would advance. I’m open to other suggestions as well. What sort of project would you assign with this data?