[18541] in cryptography@c2.net mail archive
Re: Java: Helping the world build bigger idiots
daemon@ATHENA.MIT.EDU (Jerrold Leichter)
Wed Sep 21 16:19:49 2005
X-Original-To: cryptography@metzdowd.com
X-Original-To: cryptography@metzdowd.com
Date: Wed, 21 Sep 2005 12:27:53 -0400 (EDT)
From: Jerrold Leichter <leichter@smarts.com>
To: cryptography@metzdowd.com
In-Reply-To: <nospam-1127262695.02233@iliad.gbch.net>
| > One thing to consider is that an idiom like this solves an annoying problem.
| > Consider a linear search through an array:
| >
| > for (i = 0; i < lim; i++)
| > { if (a[i] == target)
| > { <do something>
| > break;
| > }
| > }
| > /*
| > * Did we get here because we matched or because we
| > * failed to match?
| > */
|
| No, we got here because we didn't know basic C usage. Come on
| people, please stop creating these fake illustrations.
Oh, come on. This loop has a trivial increment and a trivial stopping
condition, for the purpose of illustration. But even here, it's not so
simple. Better style in general is to limit the loop variable's scope to the
loop:
for (int i = 0; i < lim; i++)
{ }
Now i isn't accessible after the loop is done. My personal style has always
been to treat the loop variable as local to the loop, even when C didn't let
you declare it that way. There are exceptions - especially cases where you
traverse the same array in two consecutive loops, the second picking up where
the first ended - but I've generally found that to be a better style.
| A real C programmer would have known that, if i == lim, there
| was no match. This is so trivial it beggars belief that it
| needs to be pointed out in a forum like this.
|
| > Personally, I sometimes use:
| >
| > for (i = 0; i < lim; i++)
| > { if (a[i] == target)
| > goto found;
| > }
| >
| > This draws shock and horror from some code readers, but I don't care. :-)
| > Note how much it looks like the exception-based code.
|
| It only draws gasps from people who don't know C. The goto that
| is famously considered harmful is not spelled "goto" in C, but
| rather "longjmp"; it's not used all that often and does need
| careful handling. The C goto statement is purely a local goto
| and scares nobody who has grown up.
Nice to know we're all adults here :-)
-- Jerry
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