Re: Question about this piece of code.

From:
"Alf P. Steinbach" <alfps@start.no>
Newsgroups:
comp.lang.c++
Date:
Sun, 10 Aug 2008 20:14:47 +0200
Message-ID:
<3fGdnYofTfoAsgLVnZ2dnUVZ_qvinZ2d@posted.comnet>
* Jianwei Sun:

Hello AnonMail2005@gmail.com,

On Aug 10, 11:18 am, Jianwei Sun <jsunnewsgr...@gmail.com> wrote:

I am reading a peice of code which is at the following link:
http://www.brpreiss.com/books/opus4/html/page141.html#SECTION0071230
00 000000000000

The code is like this:

Object& StackAsLinkedList::Pop()
{
if(count==0)
throw domain_error("stack is empty");
Object& const result=*list.First();
list.Extract(&result);
--count;
return result;
}
Does this code return a reference to local variable result? If this
is
the case, then this code has problem?
Thanks,
J.W.

The list extract function is here:

http://www.brpreiss.com/books/opus4/html/page98.html#SECTION005210000
...- Hide quoted text -

- Show quoted text -


If we ignore that result is a const and the return type is non-const,
it would seem that the returned value (a reference) refers to an
object that has been deleted inside the Extract function. This, of
course, is wrong.


Thank you for verify, I just want to make sure I didn't miss something
obvious since the author who maintains
this tutorial is a very knowledgeable person and this book is a 5-star
book on amazon.com


Perhaps the author is very knowledgable about data structures and algorithms,
but just doesn't know even the basics about C++ and programming in general?

For the code isn't even syntactically correct and should not compile, and the
use of a reference here is extremely non-idiomatic and misleading, but the basic
algorith and data structure logic could be sound: it seems that it could work,
if expressed correctly, but that could be like interpreting as favorably as
possible the writings of a chimpanzee posing as a college professor.

So, I'm pretty sure that if you look up the ACCU C++-oriented review of that
book it will be very far from 5 stars: on the other end of the scale. ;-)

Cheers, & hth.,

- Alf

--
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