Troubles with Error Messages

Error messages, in theory, are there to help programmers. Of course there are problems with then in practice. With students, the biggest problem is that  they don’t read the messages. I’ve long ago lost count of the times a student told me they had an error but can’t tell me what it is (or was) because they closed it without reading it.  Getting students to read the message and to try to work out the problem themselves can be a struggle but one we have to attempt.

Even if they do read the message, messages are not always clear. Have you seen this poem?

Roses are red
Violets are blue
Missing {
at Line 32

Seems simple enough but that can be deceiving. Often the message doesn’t actually give the right line. The reasons for this can be complicated for a beginner, or even an experienced programmer, to understand. It is a constant source of frustration.  At least one knows that a missing curly brace is (probably) the problem even if we are not really sure where it is missing from.

Other messages are less helpful because the programmer lacks knowledge to understand the words being used.  Or the message just does a poor job of explaining the problem.

Why are error messages less than helpful? Many reasons. One is that error messages are not fun and interesting to write. There are also strict limitations on the number of characters allowed. Still another is that the person writing the message is often so familiar with the software and the error that they write something that, while meaningful to them, is somewhat opaque to people newer to the software.

Reading error messages is not just a problem for students of course. When I was doing technical support for professional developers I would regularly get calls asking to explain an error message. A little secret here – a good explanation could often be found in the documentation! More than once I just looked up a message and read from the documentation. Even the explanation in the documentation needs a little help sometimes but it is a great place to start.

When teaching beginners we don’t often spend a lot of time on error handling which means we don’t spend much time talking about writing good error messages.  We do ask students to write messages in programs about games over and winning and losing. Occasionally we have to suggest rather strongly that an error message that calls the user “an idiot” is perhaps not appropriate.

Perhaps we should spend a bit more time on error handling and as part of that talk about good error messages. Maybe if we had beginners talking about the error messages they see from their systems and how they could do better we;d get better error messages later when (if) they turn professional?

Regardless, I think error messages should be a bigger part of the conversation. Reading them, researching what they mean, and thinking about how they could be done better.

What Do Computer Science Teachers Need For Professional Development

Mike Zamansky had a great post called Trends In Professional Development in CS - it's not all good. We’re still at a very interesting place in the development of computer science education.  The shortage of qualified CS teachers is becoming more acute and more and more schools and school systems attempt to expand CS education. Professional development is also growing as well As Mike reports a lot of it is from content providers who have a vested interest in promoting their content.

What do CS teachers really need for professional development? Learning about tools and established curriculum is helpful for sure. Increasingly though, we are seeing teachers without a strong CS background being asked to teach CS classes. Few would ask teachers who could not speak Spanish to teach AP Spanish but that doesn’t mean that teachers who don’t know a lot of CS aren’t asked to teach AP CS courses. Weird isn’t it?

So clearly a lot of teachers need content knowledge. Learning along with students using canned curriculum sort of works I suppose but to be that feels like everyone is going to get shortchanged.  We are starting to see more pre-service programs for CS teachers. The program Mike Zamansky is helping to build at Hunter College for example. And there is usually the option, time consuming and possibly expensive, of taking regular university CS courses. The key thing is that school systems have to be supportive (with time and money) for teachers to get this training. A week or two in the summer is not going to cut it for CS content anymore than a week or two is enough to prepare is Physics or Chemistry teacher.

The other thing CS teachers need to know is how to teach CS. Content alone isn’t enough. As someone who entered teaching with lots of CS knowledge but nothing more than having been a student in terms of how to teach. That’s not as much as some might think! Teaching CS is different from a lot of other subjects. Similar in some ways for sure but also different. Learning how to use specific curriculum is helpful and I have learned a lot from content providers over the years. We could do more. While pre-service programs are starting to come online and include this sort of thing there is still a shortage of such education for in-service teachers.

We’re starting to see more “how to teach” sessions in conferences like CSTA. The one I lead in 2020 was very well attended which suggests that there is demand. Books are starting to come out as well. Computer Science in K-12: An A-to-Z Handbook on Teaching Programming edited by Shuchi Grover is my favorite and one I recommend highly.

We still need a lot of research on how to teach computer science. That looks like it is increasing as well. That’s great especially if researchers share their results in ways that are accusable to teachers. Not all K-12 teachers have access to papers that are behind paywalls. I’m sure hoping to see more research based teaching techniques at CSTA this summer.

What do you want to see in CS teacher professional development? Who is doing it well? Any other books to recommend? Feel free to add in the comments.

Writing The Wordle Clone

Kelly Powers posted a Wordle project document on the AP CS A Teachers Facebook page. It’s solid as one would expect from Kelly who is just awesome. It inspired me to write my own Wordle clone to better understand what is involved from a student project perspective. Of course I did it my way.

A Wordle project must consist of several parts:

• Pick a word
• Accept a guess from the player
• Analyze the player’s guess
• Look for letters in the right place in the work
• Look for letters in the word but not in the right place
• Look for letters not in the target word
• Give the player feedback
• Repeat accept and analyze until player finds the work or had 6 tries
• Report on end of game

Most of this is platform and language independent. The exception is giving the player feedback. I’ll get back to that.

Picking a word can be easy (a hard coded selection – great for debugging) or a little more involved (picking randomly from a list). The list can be a small array or a large one that involved reading from a file. Which you select depends mostly on where students are with regards to reading from files and filling arrays or array lists. I have links to two large lists of 5 letter words at the end of the post. The first is one that I use and is on my web page. The other is a larger list on GitHub.

Accepting the player guess can be as easy as reading a work from a line. Analyzing the word is the first place where students have to think things our. String methods like SubString for looking at individual letters, IndexOf for locating specific letters in a string, and others are very handy here. Once can create new arrays of a) letters that are in the right place b) letters in the word but not the right place, and c) letters not in the word at all can be useful. I’ve sure there are lots of other ways as well. Much will depend on how you display the results to the player.

Feedback! One can reprint the player’s guess with letters that are in the correct place in UPPERCASE, letters in the word but the wrong place in lowercase, and empty spaces for letters that are not in the word at all. That’s probably a great way if you are totally text based. If you are graphically minded, you can try to duplicate how the web based game displays results.

There are lost of graphic libraries that will let programmers display things graphically. Swing in Java, Processing (for Java or Python), as well as many online drag and drop tools will all do this. I worry that for most of them students spend more time on the graphics than on the nuts and bolts of the rest of the program.

I’ve gotten a bit, ok maybe more than a bit, spoiled using Visual Studio and Windows Form projects in Visual Basic or C#. That is what I used to program my solution (image right). I have 6 arrays of label boxes. Yes, I should have used a two dimensional array. That would have made some things easier but I was not trying to make the best version ever. A lot of beginning programming classes skip multi-dimension arrays as well so I wanted to see how it would be done without them.

As each letter of a guess was entered on the keyboard it was entered in a label box. After all 5 letters for a guess was entered I checked all the letters against the Wordle word and the back color of the box was changed appropriately. The result was pleasing.

Checking for a winner was a matter of checking the state of all 5 label boxes in the row array. This would be similar in a text based display as well.

All in all a very doable project for many programming classes. And it is current which I see as a plus. Additionally students will probably be very happy to play help debug their peer’s programs.

• List of five letter words (8,258)
• GitHub source of five letter words (12,972) 

Computer Science for the sake of ?

My grandson in kindergarten has a class in reading. It makes sense as he is just learning how to read. Over time, school spends less time teaching how to read and a lot more time using using reading to support learning. For many years, I have been saying that computer science and its tools should be the same.

Early on I thought of things like using spreadsheets to look at data. More and more I see programming as a learning tool as well. But coming back to data. I recently watched a TEDx talk by Emmanuel Schanzer titled Four Ingredients for K-12 Data Science. Watch it. It’s cool. In any case, it is clear that Bootstrap Data Science takes things I used to think about to a whole new level.  I saw a presentation on this by students at a conference in the before times and was impressed with what students had learned.

Now Bootstrap is probably best known for their mix of computer science and algebra but they are moving into more areas of the curriculum and I think that is a great thing.

I’ve also mentioned Mark Guzdial’s work in teaspoon languages. (task-specific programming => TSP => Teaspoon) Mark’s work involves “adding a teaspoon of computing into other subjects.” It’s still some early days on this effort but it looks very promising.

Last spring, while I was teaching at a new (to me) school I spend some time with a teacher of astronomy. He was having his students write Python programs to solve astrophysics problems. Faster and more accurate than the slide rule stuff back in my day.

In many ways, I think the CS 4 All movement has been a bit too focused on stand alone computer science classes. Those have a role for sure and some great value. But ultimately, computer science is used in just about every discipline we have today. Teaching it in those various contexts and using CS to help learn those other areas of knowledge is were CS education can have its greatest impact. And greatest relevance. Finding more ways to do that should be a priority. Not just for CS bot for all areas of teaching and learning.

Planning Before Coding

After all these years one would think I would know better. But it turns out that when coding for fun I don’t always do the planning that I should. It always comes back to hurt me. If you have been reading this blog lately you know that I have been playing with a Wordle solver. It’s going well. But ..

I started well. I identified several thins my solver should look for:

• Words that include letters I know are in the word
• Words that don’t include letters I know are not in the word.
• Words where a letter (or letters) are in specific positions
• Words that include required letters that are not in positions I know they don't  belong

I coded up the first two options first and a partial implementation of the third option. So far so good. The problem came when I wanted to add an implementation of the fourth option and a more complete implementation of the third. The problem is that I had neglected to plan for where in the code I would do those checks. I tried tossing them in to the existing method but it was a mess. I had to change a good bit of the code around filtering words to make it both work and be more understandable.

In hindsight, I think I would have been better off creating stub methods for all the options and filling them in one by one. It’s a technique I recommend to students all the time so I should have thought of it myself. This would have given me a stronger framework from the beginning and made my life easier.

In any case, this exercise was a reminder not to start coding before enough of the planning has been done. I know the mod these days is to write fast and break things with a lot of rewriting. I find that to be less than ideal for me though.

How Do You Define a Computer Scientist

The last few days have seem some social media discussion about requirements for a computer scientist. Is Calculus a requirement? Is Assembly/machine language a requirement? Among the “yes” and “no” answers there are requests for a definition of a computer scientist. I doubt we could get agreement on a single definition. The mental image people have of a computer scientist is closely related to what knowledge they think a computer scientist should have.

In K-12 education I think we should be very careful and drawing too narrow a definition of a computer scientist. If truth there are many kinds of computer scientist and each kind has its own requirements.

Someone exploring the science of compiler design and code optimization probably does need a solid understanding of machine language. Someone whose focus is on machine learning probably doesn’t as their tools will be at a higher level than the machine. Computer cryptography could probably use a good dose of Calculus. As could some other focuses. Does someone studying user interface? Maybe not.

Should students focus on a special area while in (or before) high school? I don’t think so. They'll have more opportunity to find a focus later. Is Calculus useful? Sure, and for more than just computer science. But there isn’t much that students will do in your average HS CS course that requires it.

The same is true of assembly language. Assembly language clearly gives students greater understanding of the machine below. Some exposure to it is good for programmers and computer scientists. Should it be required? Again, probably not at any depth unless there is a specific need to it.

Back when I was learning CS we had a computer without the memory for an operating system. Programming in assembly language was required. I had to learn how to program subtraction, division, and multiplication on a machine that lacked built-in instructions for those operations. A great learning experience but not one I found much use for later in my (almost 50 year) career. I did work on some projects that required a firm knowledge of the execution speed of different instructions. And knowledge of assembly language helped there. But we don’t see that sort of need except in rare cases these days.

What was required knowledge 50 years ago may not be the same as required knowledge today.  We have to avoid the blind assumption that what we learned and the way we learned “back in the day” is the way things have to be today.

Wordle Solving For Fun and Coding

After my post the other day (Is Wordle A Project To Assign Students to Program?) I got thinking about solver help for Wordle. I happen to have a huge word list I got some somewhere some time ago. For various reasons I had written a program to make sub list files of words of a specific length. So of course I have a list of 5 letter words – something over 8,000 of them. So that is a start.

Phase one of my program was to find all the words that had a specific letter in a specific location. That narrows things down a bit was not near enough. Phase two was to ignore words that had specific letters which I knew were not in the correct answer. That was very helpful.

If I don’t know where any letters were I was not getting close enough. So I added a method to include all words that had specific letters in any position while ignoring words with specific other letters.

You would be surprised at how many 5 letter words have the same five letters but in different position by the way. On the other hand if you get enough information about what letters to exclude, what letters to include, and one or more letters with a specific location than finding the answer is pretty easy.

This was a fun (for me anyway) coding exercise. Will it be fun for students? I have no idea. Let me know if you have an opinion or try it with students.

Is Wordle A Project To Assign Students to Program?

Seems like a lot of people are playing Wordle on social media these days. Have you tried it? It’s a word/letter version of old Mastermind game The idea is that you enter a five letter word and the game tells you if you have a letter from the word in the correct place (green highlight), a letter from the word in the wrong place (gold highlight), or a letter that isn’t in the word (grey highlight). You have 6 attempts to get it right.

You can read more about the game many places but I read about it here.

It’s a fun game to play especially if word puzzles are your thing. I’ve had students program Mastermind in the past. It goes pretty well. This might be a fun variation for students as well. The current tie in with social media may be a plus as well.

Oh, wait, can we program the computer to solve Wordles?

Looking Back on Computer Science Education in 2021

I’ve never felt less prepared to write a look back on CS education than I do today. I’ve been retired from most of the year and the world has been changed a bit because of COVID. I have noticed some things have clearly happened. One is the increase in online development tools which I talked about a year ago. The other is an apparent growth in cyber security education.

I’ve also noticed some increase in virtual reality programming courses as well. How that will go is anyone’s guess. There are two barriers. One is that VR hardware is still expensive. It’s not just devices like the Oculus but also computers capable enough to support VR and its development. A lack of training is also a barrier. Most teachers seem to be learning on their own with help from documentation and videos from companies. That and some support through social media from other teachers.

The Unity Teach Community has well over 2,000 members and is very active. I highly recommend it if you are looking to get involved in teaching VR.

Online teaching and programming tools have really taken off. The code.org courses support this sort of thing but they are far from the only option. CodeHS for example shows up a lot in social media discussions. As does Coding Rooms. And repl.it. I should probably collect a list of them for a future post. Perhaps you could add your favorites as comments and help me out?

Cyber security has also seen a lot of growth. Cyber.org has a lot of materials and provide cyber security professional development. Social media support for teachers coming from teachers has also been growing. I recommend the Cybersecurity Educators Facebook group. Over 1,000 members and active and growing. This field is going to boom as security gets more attention all the time.

Every year I expect  the Internet of Things to take off but it never really does. The pandemic has made doing any sort of physical computing more difficult. But I keep hoping.

Machine learning and artificial intelligence didn’t seem to pick up a great deal but it is growing. AI 4 K12 has a lot of useful resources from teachers and I recommend checking them out. Most of what I see in K-12 AI is units in existing courses and not specific full courses. That’s probably best at the K-12 level. The math and coding involved in creating AI from scratch is intense. Learning how to use existing tools is both useful and age appropriate.

So progress has been made and that’s a good thing. 2022 should be interesting. Hopefully, in a good way.

Computer Science Education Week 2021

Well, its CS Ed Week again. Still no cards in the Hallmark store for it. I’ll get back to that in a moment. CS Ed Week has long been a time to introduce more students to computer science. When it started there were only small percentage of schools that offered any computer science education at all. We’ve made a lot of progress. There is still a long way to go though as even though more schools offer CS the number of students taking it are still very low.

There is no shortage of ways to introduce students to computer science during CS Ed Week. Hour of Code is probably the best known and widest platform in use. And it is a great one.Miles Berry has several activates in his blog post Five (out of twenty) things to do with a computer with more information about using Turtles one another blog post - Make a Turtle!

I never made a big deal of CS Ed Week when I was teaching for the very simple reason that the school I was teaching at required a full year (or two semesters) of computer science as a graduation requirement. Getting students to take courses was not an issue. We spent more time trying to make the course interesting, relevant, and even fun while being rigorous.

In hind sight, perhaps I missed an opportunity to have students celebrate what they were doing though.  There are some activates not involving code that we could have done. Maybe you want to try them as well.

Grace Hopper – The timing of CS Ed Week is the week that includes Grace Hopper’s birthday – December 9th. So it is a good time to talk about her and other women in computing. Women have played a huge and often underrecognized role in computing. Maybe younger students would like to make Grace Hopper birthday cards?

CSTA ran a number of contests for student for CS Ed Week some years ago. They make good activities. For example, filming a PSA video to promote computer science in general or specific courses. Posters to promote taking a CS course might be fun. In fact, have students create posters for a specific course that might be over looked. That may help fill courses that students don’t understand from a course description in a program of studies.

Speaking of programs of studies, ask students to write their own description of the course they are or have taken. You may gain insights into how students view the course that help you make the course better.

About that greeting cards, what would a CS Ed Week greeting card look like? Ask students to create some. Let’s make is have a celebratory feel!

First - Understand the Problem

Things are different for me being retired. I don’t get the blogging inspiration the way I used to. Today a post by Mike Zamansky (Work through the example!!!!!) got me thinking. I used to talk to students about problem solving and one of the things I tried to highlight was the need to understand the problem as completely as possible.

All too often students read or listen to instructions lightly and make assumptions that are not really supported by what has been presented to them. It is often tempting to skim and assume with the idea that it will save time. It works often enough, for simple enough problems, to help people to fall into the trap of thinking they are smart enough to do this always. Until it doesn’t work.

It’s hard to get students to focus on understanding the problem completely. Honestly, it can be hard for more experienced people to do this as well. The urge to jump into the coding is strong. I have been known to start coding too early myself. The more important the project/problem the more important it is to make sure you really understand the problem.

In what seems like a different life I was a developer in an operating system group. The sub team I was on was writing a new print/batch subsystem from scratch. The three of us spent weeks looking at what features should be there and how they should be set up. We spent more weeks designing the code. All before we wrote a line of code. Honestly, the groups leadership was on our case to start coding before we were done understanding and planning. Long story short, we finished on-time without having to work crazy overtime hours. Planning paid off.

It’s a story I told regularly to students over the years. It may or may not have helped but I tried.

Money is Hard in Programming

Last week I wrote about the making change for a dollar project. It got me thinking about how hard dealing with money in programming really is. The problem with money is that 1/10 is an infinitely repeating fraction in Binary.If one adds 1/10

Take the following C$ code.

double penny = 1.0 / 10.0;
double dime = 0.0;
Console.WriteLine(penny);  
for (int I = 0; I < 100; I++)
{
     dime += penny;
}
if (dime == 10.0) Console.WriteLine("Dime");
Console.WriteLine(dime);

One might expect that the word “dime” would be printed but it’s not. What this code actually prints is the following.

0.1
9.99999999999998

The 0.1 is expected but as you can see, adding the 0.1 100 times doesn’t give exactly 10.0. The problem often doesn’t show up right away. This sort of thing often confuses beginners because the programming language “helpfully” hides the issue. When I had the program display the value of “dime” after every addition the discrepancy don’t show up until around 6.0.

5.8
5.9
5.99999999999999

It’s not only beginners who struggle with this issue. It’s a pretty common issue and some languages support a currency data type for that reason. The currency data type adds some overhead to operations and not everyone is a fan of using it. A different alternative is to use integers and insert a decimal point on display.

One of the first programming languages I used for business related software, called DIBOL, didn’t support floating point numbers at all. It supported 18 digits of integer accuracy. It was an interesting language. Using it did make it easier for me to think about using integers for money later in my career though. Most beginners don’t have that sort of a helpful start. They are used to thinking in digital rather than binary. To my way of thinking this reinforces my thinking that learning binary is an important part of computer science education.

How Many Ways to Make a Dollar

I ran into a reminder of an interesting programming problem the other day. One I meant to use with students but never did. Other teachers I know do use it. Simply pot, how many possible combinations of coins are there that add up to a dollar. It’s easily solved with a set of nested loops like the ones below.

int count = 0;

for (int halves = 0; halves <= 2; halves++)
{
     for (int quarter = 0; quarter <= 4; quarter++)
     {
         for (int dimes = 0; dimes <= 10; dimes++)
         {
             for (int nickels = 0; nickels <= 20; nickels++)
             {
                 for (int penny = 0; penny <= 100; penny++)
                 {
                     int value = halves * 50 + quarter * 25 + dimes * 10 + nickels * 5 + penny;
                     if (value == 100)
                     {
                         count++;
                     }
                 }
             }
         }
     }
}
Console.WriteLine(count);

It’s pretty straight forward. The key thing is understanding what coins there are and what their value it. The code above doesn’t include a dollar coin. Should it? Probably but it depends on the way the problem is specified. Also these are the coins currently being minted. Over the history of the country there have been a number of other coins in circulation

US TREASURY: What denominations of coins are no longer being produced?

There are quite a few denominations of coins that the United States Mint does not produce any longer for general circulation. They are the half-cent coin, the two-cent coin, the three-cent coin, the half-dime coin (although it was replaced by the five-cent coin), a twenty-cent coins, and the various denominations of gold coins. Although the Mint does produce a series of gold bullion coins, these are not intended for circulation.

The problem would be more interesting if some of these were allowed. I keep thinking that there must be another way to solve the problem though. I just can’t think of what it might be.

[Edit] Jeremiah Simmons shared information about solving this problem using Dynamic Programming. It's more complicated but scales better. Take a look. Understanding The Coin Change Problem With Dynamic Programming

It is so sawesome when educators share ideas with each other.

Define Learn To Code

I saw an interesting question today on Twitter:

Hey coding enthusiasts! In your opinion, what's the best laptop for students to learn how to code on? #edchat #edtechchat #pdchat

— Mary Jo Madda (@MJMadda) September 30, 2021

My first response is that there is no definitive answer to that question. I thought about it for a while. One can learn to program by hooking a Raspberry Pi to a monitor, keyboard, and mouse and firing up Thonny and learn Python. One can use any number of online IDEs and a Chrome book. The last classes I taught had a mix of students running Eclipse and Processing on Mac and PC laptops with no appreciable difference. In short, does the computer even matter?

Maybe there is a question that has to be asked and answered before discussing the right or best laptop to use. That question is “what does it mean to “learn how to code?” I suspect we could have quite a long discussion on that question alone.

To me it boils down to:

• What problem are you trying to solve – how do you define “learning to code”
• What software helps you best learn to code by your definition
• What hardware runs the software you want to run

Picking the hardware should almost always be the last thing one picks. Now I have to go think about what it means to “learn how to code.”

Phun With Phone Numbers

Among the programming projects I ran into recently was one to calculate all of the combinations of letters one could make from a phone number. Companies do this sort of thing all the time. They generate the combinations and then look for words related to their business so they can use it as a mnemonic and help people remember their phone number. Probably a bigger deal before domain names than now but still useful.

How many possible combinations are there? Well, that depends. It can be a low or 2187 (3 to the 7th power) and a high of 16384 (4 to the 7th power). The highest number is for phone numbers with all 7s and/or 9s.

I’m trying to write small bits of code to keep my mind active and solving interesting (to me) little programs. Initially I didn’t care to write this program (though eventually I did) so was thinking around the problem from other directions. What if I took a word and had a program generate a phone number? That was fun. And pretty easy. So I thought about the logical (to me anyway) next step. What if I had a list of 7 letter words and generated a file with the phone numbers that matched each word?

It turns out I have a small word list with just under 114,000 words in it. Step one was building a new file with only the seven letter words in it. A nice little project that is simple even for beginners.

I borrowed the code from the earlier program that turned a word into a number. A handy thing that shows the value of methods and reusable code. I used that to create the file with a list of seven letter words and phone numbers. A list of just over 22,000 for what its worth.

When I did write the program to create all the possible combinations of characters for a phone number I had a nice data file to use to check my work. That was surprisingly helpful.

Anyone out there assigning the program to create all the combinations of letters for a phone number? What interesting solutions are students coming up with?

An AI Tutor for CS Education

Recently I came across a Microsoft Research project called AI for Programming Education. The project “goal is to build a personalized and autonomous intelligent teaching assistant (an AI Tutor) for programming education, enabling on-demand education.”

It’s an intriguing and I think ambiguous idea. I tend to be skeptical of AI tutors as a general idea. A half dozen years or so ago I attended a workshop at Microsoft Research dealing with hinting systems. In other words, how can the computer give hints to beginners. I wrote about hinting systems and the workshop here.

The tl;dr is that it is a hard problem. No surprise to teachers of course. Knowing when to hint and how much to hint is a tough problem for human teachers. For a computer AI it is going to be harder still. That’s just one part of what an AI tutor would have to be able to do.

I don’t know any more about the project than what I read on the web page (link above) and that they are looking for a CS Education researcher to help with pedagogy. CS Education/Pedagogy Research Internship Opportunity at Microsoft (AI-driven Program Synthesis in the PROSE team) That is an encouraging move.

With more and more of education moving to the cloud, more and more online curriculum being developed, and systems that are getting smarter about helping programmers to write code (IntelliCode Completion In Visual Studio (Preview) 2022), creating an AI tutor seems like a logical project to take on. I assume papers will be published. I look forward to reading more about this project over time.

Book Review–System Error: Where Big Tech Went Wrong and How We Can Reboot

System Error: Where Big Tech Went Wrong and How We Can Reboot is what you get when a top philosopher, a top political scientist, and a top computer scientist get together to think deeply about technology and society and write a book.  It’s not a book for just one group. It’s not a dry textbook or academic paper but a clearly written explanation of the issues. It’s a book for everyone.

The book talks a lot about both artificial intelligence and social computing which are more connected to each other than may be obvious at times. The social and political impacts of these topics and others are covered in a clear and understandable way without hyperbola, scaremongering, or blatant cheerleading. This is one more thing that makes it stand out from many other books on these topics.

Yes, there are parts that are scary. Yes, there are parts that are optimistic. All in all though it is as fair and open minded a book as one can get. The book askes questions that have to be asked. There is enough data and sets of facts to give one a lot to think about. In fact, I found several times that I had to put the book down to think about what I had read. It’s that sort of book.

Were I teaching Advanced Placement Computer Science today, especially Principles but also APCS A, I would assign reading from it and have class discussions. If I could not get a class set I would at least have some copies in the library put on reserve. But I’d really like my students to read it all.

This is a book that should be on some required reading lists. Computer scientists really do need to think about the “should we do this” question as much as the “can we do this” question. This is the book to start thinking that way. But policymakers need this books as well. So do business people. So give it to the polysci and business majors you know.  A lot of social scientists should read it as well – sociology, psychology, social work. Probably more. It will help one understand what people are dealing with in today’s world.

Technology is impacting society, and our democracy, in many ways. Some are obvious and some are not. If we want to have a civil society we need to think deeply about the impact of technology on individuals and organizations This book is a great way to start.

Debugging–Slow is Smooth and Smooth is Fast

Mike Zamansky had an interesting post called  What They Used To Know that got me thinking about the old days. Now Mike is a youngster and didn’t really start in computers until the 1980s.  I started in the 1970s with punch cards and batch processing. That meant that there was no instant gratification seeing your program run.

With batch, one handed their cards to an operator and some time later, hours or maybe a day, one got their cards back with a listing that showed the results. Results usually meaning a list of errors that kept the program from running.

Desk checking, studying the listing and trying to fix as many errors as possible before trying again was a bit of an art form. To this day I will often print out a program to look at the big picture in a way that still doesn’t feel effective on a screen. It’s tempting to see that as a way to go – limited opportunities to have the computer check ones code.

There are downsides to this sort of thing though. Specifically, having limited runs or at least long waits between runs encourages writing large amounts of code at a time and discourages writing and testing small pieces of code regularly.

Being able to hit “compile” every other minute though tends to encourage, or at least support, the beginner tendency to “throw some code in and see what happens.” This wastes time in the long run and often leads to ugly, hard to maintain, and inefficient code.

The military has a saying that “slow is smooth and smooth is fast” that some what applies. Slowing down to really analyze code, think smoothly, generally leads to a faster result. Tossing code in on a wing and a prayer is not smooth but chaotic. Slowing down to really look at what is happening is smooth and looks slow to the casual viewer but leads to faster results.

As I was thinking tonight and asking, “what if we limited people to some limited number of compiles a day?” It seemed like a good idea until I thought of the possible problems. That’s when I realized that external controls on speed are not the answer. Rather the answer is for developers to regulate themselves. To slow down and focus in ordered to make faster progress.

Some Simple Early Programming Projects

If you are not on Twitter you may be missing a lot of good things. For example, the other day Kelly Lougheed (@kellylougheed ) tweeted out a bunch of simple labs that only require user input and mathematical operations. I have copied them below because I want to be able to find them again later.

I’ve used unit conversion for years but it gets old. Fahrenheit to Celsius, miles to kilometers, grams to tons, you get the idea. It gets boring. Kelly has some great ideas. There is an idea from Neil Plotnick (@NeilPlotnick)  below Kelly’s ideas.

Have any more? Add them to the comments for future readers! And be sure to follow @kellylougheed and @NeilPlotnick on Twitter.

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Kelly Lougheed (@kellylougheed )

Programming activities that involve ONLY user input and mathematical operations:

• Program to calculate the tip
• Program to calculate cost per person when dining out
• Program to convert units (made-up units like Harry Potter currency okay) What else?

Also just wrote this silly lab where the user can input their age and be told their future in 10/20/30 years ("When you are X years old, you will retire to a desert island", etc.)

0.3 Fortune Teller Lab

Fortune Teller Lab Directions: Where do you see yourself in 10 years? Have the user type in their age, and tell them their future at various ages (which you calculate by adding years to their current…

docs.google.com

And for extensions, I love little math challenges that involve Ss printing out the result of mathematical expressions (getting practice with operators!). For example, there is the Four 4's Challenge, and also this 1996 Challenge:

0.3 1996 Lab

1996 Lab Directions: Use the numerals 1, 9, 9 and 6 exactly in that order to make a mathematical expression that prints the following numbers: 28, 32, 35, 38, 72, 73, 76, 77, 100 and 1000. You can…

docs.google.com

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Neil Plotnick replying to @kellylougheed

I have my students code algebra equations like the distance formula. Also stuff for geometry such as area and volume measurements. Ohms law for physics. Ideal gas laws in chemistry.

Are You Assigning Projects or Recipes?

Chris Lehmann, the amazing principal of Science Leadership Academy in Philadelphia,  says “If you assign a project and get back 30 of the same thing, that’s not a project, that is a recipe.”  Now recipes have their place for sure.  They often make a good start. I see programming as a creative thing (art/craft/skill/science/what ever) and I want to see creativity from my students.

For me this starts with day one. In my introduction to my classes I tell students that I want to see creativity. I want them to make projects their own. This can be a difficult thing for some students. There are teachers out there who do want to see the same thing from every student. It makes things easy to grade I guess. Or something.

Very often in early projects is is hard to be creative. There are only so many ways to calculate degrees Fahrenheit to Celsius. On the other hand you can ask students to find two measurements they like and convert one of them to the other. You’ll be amazed at the combinations students come up with. Sure you’ll get the simple conversion using degrees Kelvin but someone will do miles to furlongs.

Even simple programs can get creative with tools that make graphics easy. C# and Visual Basic both have the Windows Forms libraries to use but Processing can make using Java or Python colorful and graphic as well. To say nothing of a lot of block programming systems.

Of course, students getting bogged down in how a program looks can be an issue at times but that can be dealt with though conversation.

An even better way is often letting students choose their own projects. I always finish up a semester with a larger project that students select themselves. Student get very creative with those projects. The Advanced Placement Computer Science Principles course requires a Create project which serves a similar purpose.

For smaller projects it can take a bit more to encourage creativity. After all if there is known input and expected output that’s going to be the same. Here is where you want students to be creative in their code. Let students decide if they want to use a for loop, a while loop, or even a foreach loop. Decision structures can also be done in different ways. Having students turn in code that looks different is a great learning/teaching opportunity. I love showing students the different solutions that students turn in. This both encourages them to try to be different and lets them see different solutions. The idea is to open their minds to looking at problems in different ways.

The most important thing is to encourage creativity. Celebrate it!