Actually picking any sort of name is important in programming but we can focus on variable names for a bit. The CS Teaching Tips team tweets and posts a lot of great suggestions. Today they send out a tip about variable names.
Avoid using x and y as variable names to prevent students from confusing variable assignments with mathematical expressions.
I’ve been working on my variable naming for demos and sample code this semester. The x and y confusion is part of it. It’s tough because I learned in an era where short, even one character, names were the rule not the exception. Memory was expensive and long identifiers took up room in memory. Plus there was a certain amount of laziness on many people’s part. Well at least on mine. None of this is true anymore. Well that part about needing to save room with short variable names is no longer true.
Loop control variables in FORTRAN were almost always I, J, K, L, M, and N back in the 1970s. Variable names that started in those letters were automatically integers and so this was easy. Old habits die hard and I still tend to use those variables for FOR loops. I’m trying to get away from that in class.
I find that using “index” as a loop control variable, especially when the loop is iterating through a string or an array, makes things a bit more clear to students. It also helps reinforce the idea that variable names should have meaning. It’s hard to tell students, “yes I am using x, y, and I but you should all use meaningful names.” and be taken seriously. Using meaningful variable names in demos may take a little bit of extra effort but in the long run I think everyone is better off when teachers model the practice they try to teach.
There are lots more teaching tips at http://csteachingtips.org/ and you can also see tips from there on the side bar of this blog if you read it in a web browser. Follow @CSTeachingTips on Twitter too!