31
votes
Accepted
Explaining access levels and visibility in OOP
Here's an analogy that I've used for several years, and that students seem to understand. It doesn't focus on the rules, but why we have public and private and protected.
"Most of you know that I ...
- 576
31
votes
Teaching students that printf() is not the same as return
I think this is a problem where the answer is partly in the prevention. I've observed many classes where printing is the method used to access the results of calculations for several weeks, both ...
- 1,975
30
votes
Analogy for teaching recursion
The Tower of Hanoi was one of the first ways that I encountered recursion.
"The objective of the puzzle is to move the entire stack to another rod, obeying the following simple rules:
Only one disk ...
- 1,256
27
votes
Accepted
How to respond to the two-handed approach to swapping
Don't overcomplicate things. Your first instinct, that the computer only has one hand, was the correct one.
This is a regular problem that new teachers have, and it sometimes takes a few years of ...
- 32.9k
24
votes
Accepted
What are some good examples of using a stack data structure?
I once had to implement a limited undo function (undo changes to the current field, or addition/deletion of records).
The lists of undo deltas (one for field changes and one for records) were stored ...
- 356
22
votes
The Tao of TeaChing (Making Mistakes in Front of the Class)
If I catch it quickly and can easily explain the error, I use it as an example of failing up. "Ooops, look at me, here's my mistake, here's how I can learn from it."
If students catch it, and I'm not ...
- 481
22
votes
How to respond to the two-handed approach to swapping
Re-evaluate what you think is "right", because you aren't
but isn't right in computer science
This is simply incorrect. Your student can create two variables called ...
- 1,072
20
votes
Analogy for teaching recursion
Can't claim it's my own idea but I can embellish it a little...
Imagine you are entering a cinema. You sit down in a row but realise you had to sit in row 20. Being a lazy computer scientist in an ...
- 241
18
votes
Teaching students that printf() is not the same as return
I think that this problem is pretty widespread, actually. I believe that it comes from a misunderstanding of the difference between what the program/computer can know/do and what the person operating ...
- 36k
17
votes
What are some good examples of using a stack data structure?
A stack of trays in a cafeteria. I also like the pole of rings analogy.
With the trays, you can pop (take a tray) and push (return it when you're done). You can see what the top tray (first item) is (...
- 768
16
votes
Analogy for teaching recursion
The image that I kept in my head when I was learning recursion was from Dr. Seuss:
16
votes
What are some good examples of using a stack data structure?
A rather interesting analogy is that of a firearms magazine.
if we look at this picture:
It is easy to see that bullets can be inserted from the top, and only the topmost bullet is accessible. Such ...
- 6,287
16
votes
How to respond to the two-handed approach to swapping
Your problem is that you tried to let your student "program" without establishing a language. Thus they were free to write their own "language" in which you can do two things at ...
- 1,453
15
votes
Accepted
Analogy for teaching recursion
I like to use something that a student can connect with and something that they have to deal with regularly. You could choose any recursive everyday activity, but I like to choose revising an essay.
...
- 4,795
15
votes
What is a good analogy for the Object Oriented paradigm?
I've got to jump in here and talk about my experience having to help a former boss understand why the project he wanted to do wasn't possible in the time available. It came down to incompatible data ...
15
votes
What are some good examples of using a stack data structure?
The back button on a web browser is an excellent example of a stack implementation that is easily understood even by non-experts and easily demonstrated in a class. You can illustrate the stack in ...
- 151
14
votes
What are some good examples of using a stack data structure?
Check whether a string of parentheses is balanced or not.
For example, return True for these input strings:
(()())
([]{{}}[])
...
- 241
14
votes
The Tao of TeaChing (Making Mistakes in Front of the Class)
Mistakes are fine. We are human, we make mistakes.
In fact, one of the worst things you can do in teaching is to never make a mistake and to always say exactly the right thing. This is pretty much ...
- 36k
13
votes
Explaining access levels and visibility in OOP
What my teachers used was the following example, which is pretty simple and most people understood.
Your father orders a pizza. The delivery guy arrives and expects payment. The ...
- 131
13
votes
A real world example for the divide and conquer method
Back around 1985, Susan Merritt created an Inverted Taxonomy of Sorting Algorithms. The idea is that to sort an array you have two phases, the split phase and the join phase. She divided the various ...
- 36k
12
votes
What would be a good analogy for IP addresses and ports?
I used seats in the room.
The classroom has an address. So, if someone wanted to come and talk to one of the students they would come down the hall and into my room.
But, that only gets them to ...
- 3,029
12
votes
Teaching students that printf() is not the same as return
This is such a consistent trap that I ultimately created a worksheet to deal with it. At this point in my course, I have recently covered binary and hexadecimal, so I also use this worksheet as an ...
- 32.9k
11
votes
Explaining access levels and visibility in OOP
Ooh, this is one of my favorite lessons!
I don't introduce package private and protected in the same lesson as private and public, because there are 3 principles that I want them to absorb that ...
- 32.9k
11
votes
Accepted
Good, Motivating Examples for Algorithmic Complexity
I attack this problem with three "visits" over the course of two years with my students
At our first brush with Complexity, I don't spend a ton of time motivating the study of it. I introduce the ...
- 32.9k
10
votes
What are some good examples of using a stack data structure?
I like the pez dispenser.
Also the stack of papers (where the actual human interaction is never to take the top item but rather to take the second from the top.
At some point you have to talk about ...
- 1,572
10
votes
Accepted
The Tao of TeaChing (Making Mistakes in Front of the Class)
The teaching philosophy I came to as a young teacher (i.e. in my first year) was that I would ground myself in two qualities: passion and humility. (I've since added gratitude as an important third, ...
- 9,082
10
votes
Teaching students that printf() is not the same as return
Whenever I run into students who are baffled by the return concept (and in your case, them substituting it with printf), I do something like this.
I use role-play. I become one function (lets say ...
- 1,884
10
votes
What are some non-CS concepts that can be defined using BNF notation?
Going with real-world things which they should be familiar with are best, even if it is completely outside of education. As you have applied the tag for adult education, I'm going to presume it is ...
- 5,435
9
votes
Analogy for teaching recursion
Recursion as a loop
I'd present recursion as a form of a loop rather than being separate thing. Then, I'd show the students how to covert between flat form and recursive form, and discuss the pro's/...
- 897
9
votes
What is a good analogy for pass by value vs by reference?
Since I was tired of the easy IT examples which all revolved around sharing files and documents, I started using the following analogies to explain pass by value and by reference.
My cat ("Mr ...
- 1,398
Only top scored, non community-wiki answers of a minimum length are eligible