A misuse of comments is to provide information that should have been in the code. An example is when someone names variables badly and then tries to add comments describing them:

# A dictionary of families who live in each city

mydict = {

"Midtow...

Commenting involves placing Human Readable Descriptions inside of computer programs detailing what the Code is doing. Proper use of commenting can make code maintenance much easier, as well as helping make finding bugs faster. Further, commenting is very importan...

Most programmers use code that they find online. Including a reference to the source enables future readers to get the full context, such as:

• what problem was being solved
• who provided the code
• why the solution is recommended
• what commenters thought of it

It’s a good idea to comment code that someone else might consider unneeded or redundant, such as this code:

final Object value = (new JSONTokener(jsonString)).nextValue();

// Note that JSONTokener.nextValue() may return

// a value equals() to nu...

Comments should be added not just when initially writing code but also when modifying it, especially fixing bugs. Consider this comment:

// NOTE: At least in Firefox 2, if the user drags outside of the browser window,

// mouse-move (and even mouse-down) events will ...

All programs should be commented in such a manner as to easily describe (in English) the purpose of the code and any algorithms used to accomplish the purpose. A developer should be able to utilize a previously written program (or function) without ever having to look at the code, simply by readi...

Sometimes it’s necessary to check in code even though it has known limitations. While it can be tempting not to share known deficiencies in one’s code, it is better to make these explicit, such as with a TODO comment:

// TODO: We are making the decimal separator be a period,