Is there a valid reason for enforcing a maximum width of 80 characters in a code file, this day and age?

I think the practice of keeping code to 80 (or 79) columns was originally created to support people editing code on 80-column dumb terminals or on 80-column printouts. Those requirement have mostly gone away now, but there are still valid reasons to keep the 80 column rule:

• To avoid wrapping when copying code into email, web pages, and books.
• To view multiple source windows side-by-side or using a side-by-side diff viewer.
• To improve readability. Narrow code can be read quickly without having to scan your eyes from side to side.

I think the last point is the most important. Though displays have grown in size and resolution in the last few years, eyes haven't.

The origin of 80-column text formatting is earlier than 80-column terminals - the IBM punch card dates back to 1928! This is reminiscent of the (apocryphal) story that the US railway gauge was determined by the width of chariot wheels in Roman Britain.

I sometimes find it a bit constricting, but it makes sense to have some standard limit, so 80 columns it is.

Here's the same topic covered by Slashdot.

And here's an old-school Fortran Statement:

80 characters is a ridiculous limit these days. Split your code lines where it makes sense, not according to any arbitrary character limit.