hello group,
why i cant make the InputIterator of the following func-temp const?
template<typena me InputIterator, typename OutputIterator>
OutputIterator Types::Copy(Inp utIterator source,
OutputIterator first, OutputIterator last)
{
while (first != last)
*first++ = *source++;
return last;
}
thanks & hand, chris
5  2091 
On Jun 20, 4:01 pm, Chris Forone <4...@gmx.atwro te:
hello group,
why i cant make the InputIterator of the following func-temp const?
template<typena me InputIterator, typename OutputIterator>
OutputIterator Types::Copy(Inp utIterator source,
OutputIterator first, OutputIterator last)
{
while (first != last)
*first++ = *source++;
return last;
}
thanks & hand, chris
Not very understand what you mean.
and, note one of the standard copy declaration is
template<typena me In, typename Out>
Out copy(In first, In last, Out res)
-road
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Chris Forone wrote:
hello group,
why i cant make the InputIterator of the following func-temp const?
[...]
*first++ = *source++;
^^
[...]
You are post-incrementing the "source" variable, so it obviously cannot
be constant. If you need it to be const for whatever reason (eg. someone
else wrote the header and you cannot change it), just make a copy of it
(assuming the InputIterator:: operator= is defined and works as expected):
InputIterator sourceCopy = source;
while (first != last)
*first++ = *sourceCopy++;
Otherwise, passing by value as in your current implementation is just fine.
I suppose, though, that you meant "const" as "iterator cannot be used to
change pointed value". I'm afraid you have to define a
ConstInputItera tor for that.
Cheers,
- -Federico
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Federico Zenith schrieb:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Chris Forone wrote:
>hello group,
why i cant make the InputIterator of the following func-temp const?
[...]
*first++ = *source++;
^^
>[...]
You are post-incrementing the "source" variable, so it obviously cannot
be constant. If you need it to be const for whatever reason (eg. someone
else wrote the header and you cannot change it), just make a copy of it
(assuming the InputIterator:: operator= is defined and works as expected):
InputIterator sourceCopy = source;
while (first != last)
*first++ = *sourceCopy++;
Otherwise, passing by value as in your current implementation is just fine.
I suppose, though, that you meant "const" as "iterator cannot be used to
change pointed value". I'm afraid you have to define a
ConstInputItera tor for that.
Cheers,
- -Federico
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Version: GnuPG v1.4.5 (GNU/Linux)
Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org
iD4DBQFIW2fNBIp u+y7DlLcRAnqyAJ 4iyDYO1eUQMTsrR 8aIQDKTiqY4KwCY lC8c
E+Y9XR4j/kCu3kk320KOfg==
=z4Ib
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thanks a lot, thats it!
cheers, chris
Road.Tang schrieb:
On Jun 20, 4:01 pm, Chris Forone <4...@gmx.atwro te:
>hello group,
why i cant make the InputIterator of the following func-temp const?
template<typen ame InputIterator, typename OutputIterator>
OutputIterat or Types::Copy(Inp utIterator source,
OutputIterator first, OutputIterator last)
{
while (first != last)
*first++ = *source++;
return last;
}
thanks & hand, chris
Not very understand what you mean.
and, note one of the standard copy declaration is
template<typena me In, typename Out>
Out copy(In first, In last, Out res)
-road
i know the std::copy in std::algorithm. i need a target-limited version
to copy with streambuf_itera tor to std::valarray in multiple steps...
cheers, chris
On Jun 20, 10:01 am, Chris Forone <4...@gmx.atwro te:
why i cant make the InputIterator of the following func-temp
const?
template<typena me InputIterator, typename OutputIterator>
OutputIterator Types::Copy(Inp utIterator source,
OutputIterator first, OutputIterator last)
{
while (first != last)
*first++ = *source++;
return last;
}
Because you modify it in the function. You can instantiate the
algorithm with const_iterator, however, if that's what you want.
--
James Kanze (GABI Software) email:ja******* **@gmail.com
Conseils en informatique orientée objet/
Beratung in objektorientier ter Datenverarbeitu ng
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