When should I add comments to my code? [closed]

Answer 1

I tend to put basic comments as I'm going, just to remind myself what I was thinking at the time when I wrote it (i.e. why I wrote it that way). I do this especially if it's code that looks like it might be wrong but is actually right, or code that has an inherent race condition that I don't care about, or code that might not be optimal but is a quick way to get something working, so that even ten minutes later when I go back and look at it I can see that I've thought about the problem already and don't have to waste any brain cycles on it.

When the code is more complete, I'll often go back and review the comments I've written and then have a think about whether I still think the decisions made are reasonable, and whether things could be done better. I'll also often expand the basic comment into a longer comment that's more useful for other people when they come to maintain the code; I usually save comment expansion to the end because a lot of the time basic comments just get deleted during refactoring, so writing a long comment is a waste of time until you know you're going to keep it.

In a nutshell, write basic comments as you go along, and then improve them as your code becomes more stable.

Oh, and also, any time you review a bit of existing code and you're struck with a WTF?! moment but then realise the code is actually decent, put a comment in to save yourself and the next person time when they look at it in the future.

Answer 2

Personally, I tend to write comments to summarise code where necessary - often before I write the code, as well as to save WTFs. I treat them very exactly as notes - of things to do, things that I have done this way, or will do this way, and as such they are put in when and where I feel the need for them.

Answer 3

Mostly at time when you write that code. You can go there after the function/block/whatever is done and organize your comments on fresh mind. Most of the stuff we write while coding are not meaningful later.

Answer 4

You should try writing comments BEFORE you write any code. eg

public string getCurrentUserName() {
    //init user database repository


    //retrieve logged in user


    //return name if a user is logged in, otherwise return null

}

Writing comments before you code, helps you learn how to structure your code without actually coding it and realising that you should have done it another way. It's also a good way to quickly visualise a clean solution to a complex problem without getting bogged down in implementation. It's also good because if you get interrupted, when you come back to your work you can go straight back to it, as opposed to refigure out what you have done and what you need to do next.

Not suited to all situations, but often a good option!

Answer 5

I would suggest writing comments whenever you edit any code, while you are editing it. According to Robert C. Martin in Clean Code, a disadvantage of comments is that the code can change without the comments being updated, making the comments not only useless, but dangerous. To reduce this problem, if you must use comments (because you are unable to express yourself in the code itself), make sure you update them every time you update the code.

Answer 6

Comments should reflect why you are doing the things the way you do, not what it does. Most of the time the one reading your code can read what it does.

You should explain the the things one cannot reduce from the code.