Smooth Moves

[adramolek@gmail.com]

So I had this bit of strange looking code:

if (led->m_to[i] != prev &&
(FCanCrossSelf || !_hit[led->m_to[i]->m_index]));
{
cango.push_back (i);
}

I was having a problem where it was getting into the if statement even
when the condition was supposed to be false. I could not, for the life
of me, figure out what was going on. The condition has so many braces
and arrows and things in it, and I had been staring at it for so long.
Why was it getting into the if statement when the condition was false?
I could print debugging info from inside the statement and verify it
was false. I could step through in my debugger and watch it step into
the statements, even when it evaluated to false. What was going on?

Well it's obvious when I look at it now, but after *over* an hour of
debugging, looking at conditions, looking at other code, checking for
buffer overruns in strange places, I *finally* spotted the damn extra
semicolon I accidentally typed at the end of the "if". See it? It's
right there before that left curly brace.

I slapped myself on the head pretty hard after realizing how dumb the
mistake was. It's not the first time I've spent a long time debugging
a simple syntax mistake like that.

So now, I am taking a break for a few minutes, and I am wondering:
what kinds of horror stories do people here have about silly mistakes
like this one? Hours spent debugging when you typed a j instead of an
i, or put a parenthesis in the wrong spot, an extra semicolon, a
problematic #define. There's got to be some good stories out there!

- AJ

[Paavo Helde]

Re: Smooth Moves

adramolek@gmail .com wrote in news:fa29c801-70d1-40b4-a965-cb8d79379426@
59g2000hsb.goog legroups.com:

So now, I am taking a break for a few minutes, and I am wondering:
what kinds of horror stories do people here have about silly mistakes

I think one of the best was when I accidentally entered íf instead of if.
After getting some spurious errors I spent a lot of time checking the
braces, the previous statements, semicolons etc. It never occured to me
to look at the if word itself. However, finally I noticed that the syntax
coloring had failed to color it...

And just today I copy-pasted a little function from one file to another,
and it stopped compiling, complaining that T is not a type name:

/// Cast from signed integer pointer to unsigned integer pointer or back
template<typena me T, typename U>
T sign_cast(U p) {
// .. some checks
return reinterpret_cas t<T>(p);
}

Fortunately I have the habit to (nervously?) move around in the text by
arrow keys when thinking, and I noticed that when going up or down in the
text the "template" line is jumped over. It appeared that copy-pasting
into text-mode emacs window somehow managed to screw up the linebreak
before the "template" line - probably replaced by CR, so that everything
looks OK on the screen, but the compiler thought template line was just a
continuation of the comment...

Regards
Paavo