Because a full-adder is, at root, a mathematical expression, various software models can accomplish the same results. Models are abstractions, so the only thing a model can simulate perfectly is another model.
I was involved in a debate recently about whether a full adder logic circuit is a computer. The computer science answer is: “No, not as we define a computer.”
I plan to address that answer in detail on my main blog. Here I wanted to show some of the different ways a full adder can be modeled and implemented.
To ring in the new year I thought I’d play around with an old friend from my earliest programming days, a random text generator. Back then (over 30 years ago), but a little bit always, a good way to practice programming is by working on small, relatively easy, but still fun, programs.
Simple games are common choice, but not the only one. (I’ve probably written a version of Mastermind in every programming language I know.) Another fun choice is various image or text generators (or processors). Random text generators, in particular, offer a range of complexity depending on your taste and time.
There’s a general ethic these days — that anyone can code — and like a lot of things, there’s some truth to it, but also some silliness. As usual, it really depends on what we mean by “anyone can code.”
If we mean it in the same way we might say, “anyone can drive,” I think it’s silly. But if we mean in the same way we might say, “anyone can doctor (or lawyer),” well, then I still think it’s silly.
I cracked up when I saw this recent xkcd cartoon. Randall Munroe rarely fails to deliver, but this one especially caught my eye. It’s painfully on-point and quite dismaying on at least two points:
Firstly, that it should still be this bad given all the time, money, and attention, it has received is reason alone for dismay. Part of the problem here may be that we haven’t admitted how hard software is to get right.
But, secondly, software is central to our lives now — far more than airplanes, and even more likely than elevator rides. You might ride an elevator, at most, a dozen times a day, but software enters your life more times than that.
Especially if you use a mobile computing device!
Sometimes ya gotta laugh. I just spent nearly an hour chasing one of those bugs that “can’t be happening” because “the code looks absolutely correct (as far as I can tell).” Of course, the bug, once you find it, was always hiding in plain view.
This time the fix involved adding just two characters, incidentally improving the program semantics, and very much reminded me of the old joke about the huge cargo ship that breaks down at sea…
In the unlikely event anyone is reading this, and, more in the original spirit of “web logs“, as much a diary entry to record both the passing of time and the moment, after a long period of quiet, and in the long-winded run-on way that I sometimes have, a post.
When it comes to what makes a computer (or any other) language a programming language, there are three characteristics usually required:
- Saving state (variables)
- Selecting a code path (if-then)
- Iteration or recursion (or equivalent)
This post is just a brief note (for a friend) about the third item and why it allows three distinct options.