alanstokes@my-dejanews.com wrote:

> Is it legitimate to pass to std::for_each a function (or function object)
> which will modify its parameter - so that each item in the sequence gets
> modified?

Yes, perfectly legitimate

> I can't see anything one way or the other in the standard. for_each is
> described under the heading "Non-modifying sequence operations", but I don't
> think this term is anywhere defined [mutter grumble stupid Acrobat doesn't
> seem to be able to find anything with a hyphen in it] - and are headings
> normative anyway? And the description of for_each in 25.1.1 doesn't leave me
> any the wiser.

It's there because moving things in a different section is error prone,
or
because no one cared to move it.

> The Dinkumware reference, which I have a great deal of respect for, states
> that the function must not modify the element, but I'd prefer chapter and
> verse on this.

We got rid of this non sens. Perhaps the reference you cite is out of
date.

--

Valentin Bonnard                mailto:bonnardv@pratique.fr
info about C++/a propos du C++: http://pages.pratique.fr/~bonnardv/


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Is it legitimate to pass to std::for_each a function (or function object)
which will modify its parameter - so that each item in the sequence gets
modified?

I can't see anything one way or the other in the standard. for_each is
described under the heading "Non-modifying sequence operations", but I don't
think this term is anywhere defined [mutter grumble stupid Acrobat doesn't
seem to be able to find anything with a hyphen in it] - and are headings
normative anyway? And the description of for_each in 25.1.1 doesn't leave me
any the wiser.

The Dinkumware reference, which I have a great deal of respect for, states
that the function must not modify the element, but I'd prefer chapter and
verse on this.

--
- Alan

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