[cridal]

Can people please stop using the "make adder" examples? Can't you come up with something original and fresh? The triviality of what is acomplished in such case actually obscures the usefulness and power of the concept. As a result, the novice will interpret the end product as some useless, magical mambo jumbo that doesn't give him much. So who cares if I can get a function that adds a number to something. I have a "+" for that. Give me a use case that I can admire...

Why do you want me to appreciate a ferrari if all you do with it is go pick up some groceries...

[chrismear]

I agree that for a novice a trivial example doesn't inspire them to learn more. But an experienced programmer who just wasn't familiar with this concept might appreciate more a stripped-down example like this that demonstrates the essentials of the idea. And in general, different people have different learning styles.

[BigZaphod]

That's why I use a counter as a simple demo - you see state changing with each call and it's done without using a global or passing in some kind of context object. It's not a lot more powerful than the adder, but in my experience it more often generates a "what the hell..." kind of reaction to the uninitiated.

[scott_s]

"Original and fresh" is generally not conducive to understanding. People are more likely to understand a new concept when that new concept is applied to concepts they already understand. It lets them filter out everything but that concept.