Etydhv

I am a young professor teaching a data structures course for the first time. I'm teaching at an engineering college that provides an academic degree, but the focus is preparing future computer programmers, not academics.

Before the start of the semester I decided to present the algorithms as java code, instead of pseudocode. I felt that this would make the presentation more precise, and show the students how to put these algorithms to practical use.

My experience has been mixed. It seems like the problem is that now the students think that the various algorithms are the java code. They are complaining that, for example, I can't possibly expect them to know the counting sort algorithm, because how can they be expected to learn code by heart? So I am starting to understand the wisdom of using pseudocode.

My question, intended for other teachers, is: What has been your experience when using pseudocode vs using code?

Similar to @Vince, I think it's a good practice to do both. I don't really agree with the cooking recipe analogy, though. Pseudocode describes that the algorithm does, without going into detail how you do it.

I think perhaps a better analogy:

• Pseudocode: you need to put an egg into the flour mixture


• Actual code: pick up an egg, crack it open on the side of the bowl, and drop the egg into the container. Don't forget you need to dispose the egg shell as well.

There are so many ways to accomplish the task, and the actual code just gives the student an example of how to do it.

Presenting only the pseudocode might make some of your students loss. Presenting only the actual code would keep them in the box and get them focused too much on the details. A mixture of both would be my choice.

Actually I am of the opinion that you should not present your own code, but rather get the students to implement the algorithms you teach them, which you give in pseudocode, and give them the freedom to choose any one of a fixed set of languages that you are familiar with, such as C++/Java/Python. Really, the only way students can truly understand an algorithm is when they face the real task of implementing it, but the key ideas behind an algorithm can be sufficiently conveyed via pseudocode.

I understand your dilemma, but from a general pov it's better to present content through pseudocode. This actually gives students the freedom to explore multiple languages. When you present your code in a particular language you are making them comfortable with that language alone and they might find it hard to shift to other languages later on. The main purpose of learning algorithms is to know how they work rather than implementing them in a particular language. Regarding resources, I would suggest looking up books like Introduction to Algorithms. You can also refer to CodeMonk which is an online portal which has a collection of all known problems and algorithms to look into.

One of the key points here is that you are teaching to future engineers, even if at academic level. The very nature of engineering is solving problems by implementing a solution.

Therefore I think that presenting the pseudocode is useful to give your student the correct theoretical POV to frame the problem, BUT showing them an actual, working implementation is key to make them develop their engineering skills.

Much better would be to show them the pseudocode and make them try to come up with an implementation first, then show them yours. But this requires honing their skills first, probably.

As their skills improve, you may also dare show them more than one implementation, possibly in two or more languages. Of course this depends on their actual knowledge of the languages you are going to use. If they know only, say, Java, showing them an additional implementation in another language could backfire and confuse them more.

Of course, I'm assuming that it's not your duty to teach them another computer language, otherwise, it could be a useful approach: start with pseudocode, show a reference implementation in a known language (e.g. Java) and finally show them how to reimplement the algorithm in the new language they must learn.

I think the best is to do a comparison. The algorithm may be a cooking recipe that may be written in many languages but produce always the same cake.

Pseudo-code is like describing the recipe with pictures. There is not a unique grammar or way to "talk" in pseudo-code but anyone should be able to interpret it. By reading the pseudo-code written by someone, one may often guess what is his favorite language. The main rule is to forbid the language specific keywords.

Teaching an algorithm in a specific language is not a problem in my opinion as long as anyone understand it. But if you want someone to master this algorithm, you have to make him try it by hand. Make him do the different steps of the algorithm on a small example. In fact it is again like cooking the cake... You can remember a recipe much easier if you actually have cooked it.

1. Pseudocode helps a lot by removing anything unnecessary, and focusing entirely on the algorithm, which can already be hard to understand as is. It's also faster to express ideas : if a student wants to write a different algorithm than the one you taught them, it can be really cumbersome if they have to deal with every details of Java.




2. As other said it, it's good for student to come up with they own implementation in code of the pseudo-code algorithm. They need to really understand it, while if they just paste code or learn it by heart they won't necessarily understand every subtlety.

I think most universities do this already (mine did), but I think the best is pseudocode for the course, and real code for practical exercises.