Use comments to include notes to yourself or others. The contents of a comment do not follow any dBL rules; include anything you want. Comments are stripped out at the beginning of the program compilation process.

A program will typically contain a group of comments at the beginning of the file, containing information like the name of the program, who wrote it and when, version information, and instructions for using it. But the most important use for comments is in the code itself, to explain the code—not obvious things like this:

n++ // Add one to the variable n

(unless you’re writing example code to explain a language) but rather things like what you’re doing in the overall scheme of the program, or why you decided to do something in a particular way. Decisions that are obvious to you when you write a statement will often completely bewilder you a few months later. Write comments so that they can be read by others, and put them in as you code, since there’s rarely time to add them in after you’re done, and you may have forgotten what you did by then anyway.