Special Programming Identifiers

Now that we know that identifiers in the C programming language can be any combination of letters or numbers that start with a letter, the ability to create identifiers would seem to be wide open. And it is, almost. However, there are some identifiers which you may not use since someone else created them first. These words, called keywords, are words necessary to implement actions in your programs; in other words, they are part of the programming language. A nearly complete list is provided here; some of the keywords have been left out since you are unlikely to accidentally use them. You will be using some of these in the course you are taking, but the important issue is that you don’t try to use any of them for your own identifiers.

This is a short lesson on identifiers you may not use for your own purposes. However, there is one keyword that is specified in C but not really used, and should never be used in any high-level programming circumstance. While there is a place for comparable operations at the embedded systems level (i.e., processor-level or low-level programming), there is no place for goto in C (or any other high-level) programming. One of the forefathers of Computer Science, Edsger Dijkstra, argued that since the BASIC programming language included a goto statement, it would cause brain damage. In a little more realistic argument, it leads to very poor, very difficult to follow programming known in the software development business as "spaghetti code". It is obviously not the kind of programming you will want to develop.