Re: relational expression and increment operators

From:

Pete Becker <pete@versatilecoding.com>

Newsgroups:

comp.lang.c++.moderated

Date:

Fri, 14 Aug 2009 08:26:19 CST

Message-ID:

<Qc-dnU73L_FgzhjXnZ2dnUVZ_qmdnZ2d@giganews.com>

Kishore Yada wrote:

There is something called "sequence points" which has a role in this.
But, I haven't touched that yet.

There are no relevant sequence points in the code in question.

Logically speaking, this is what seems to happen

     if (arr[index] < arr[++index]);
gets expanded to
     ++index;
     if (arr[index] < arr[++index]);

     if ( index < ++index )
gets expanded to
     ++index
     if ( index < ++index )

Maybe. But that depends on the compiler and on the compiler settings.
The language definition says that the behavior of all of these things is
undefined, which simply means that it does not impose any requirements
on what a conforming compiler does with this code.

--
   Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of
"The Standard C++ Library Extensions: a Tutorial and Reference"
(www.petebecker.com/tr1book)

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