Re: C
Re: C
- Subject: Re: C
- From: "Alastair J.Houghton" <email@hidden>
- Date: Fri, 29 Aug 2003 23:21:36 +0100
On Friday, August 29, 2003, at 08:55 pm, David Thorp wrote:
Actually, I've just tested it without the parentheses in the while
condition, and it still works. Guess I was wrong about that
precedence comment.
Yep.
Still, I believe it's wise to put the parentheses in anyway, if for no
other reason than it's easier to read,
No, it isn't. A lot of people make this assertion, but the fact is
that it's easier to *write* (because you don't have to think), and
*not* easier to read. Consider, for example
(a - g + b * c + d / (h + i * j)) * e - f
vs
(((a - g) + (b * c) + (d / (h + (i * j)))) * e) - f
The former is very obviously easier to read. Even a Lisp programmer
would balk at the latter ;-)
It isn't safer either; if I'm working on some code that contains an
expression like the latter, there is an increased risk that I will
accidentally move one of the brackets to the wrong place whilst editing
it. Even bracket-matching in editors doesn't mitigate that risk---all
that tells you is that the expression isn't balanced (so you need to
add a bracket somewhere)... it doesn't tell you *where* to add it, and
it's very easy to make the wrong choice.
but also helps you be sure you've got it right.
It helps me to be sure that I get expressions right if I *know* at
least the basic rules regarding the use of operators in C. Now, there
are obscure cases (for example, a & b && c = what?), and in those
cases, extra brackets are arguably OK, but for the common cases you
really should know the rules.
Anyway, for the benefit of those that don't have one already, here's a
precedence table:
http://www.alastairs-place.net/blog/stuff/C Operator Precedence.pdf
(I believe it's correct; please let me know if you spot a mistake...)
Kind regards,
Alastair.
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| | >Re: C (From: David Thorp <email@hidden>) |