Prev: const is an overrated concept that is a source of extra typing and maintenan
Next: performance of map in MSVC 10b2
From: itaj sherman on 7 Apr 2010 01:50
Is there some standard/boost equivalent to a function like:

template< typename T >
T successor( T r )
{
return( ++r );
}

That can be used when the return value of operator++() is needed but
not the side effect (notice non reference parameter).

I always feel the need when using iterators and need to peek the
following element, or using reverse iterators

template< typename Container >
void foo( Container const& r )
{
for( Container::reverse_iterator aI( r.rbegin() ); aI != r.rend(); +
+aI )
{
// use successor(aI).base() or
Container::iterator const bI( successor(aI).base() );
// use bI...
}
}




--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Jeff Flinn on 7 Apr 2010 05:58
itaj sherman wrote:
> Is there some standard/boost equivalent to a function like:
>
> template< typename T >
> T successor( T r )
> {
> return( ++r );
> }
>
> That can be used when the return value of operator++() is needed but
> not the side effect (notice non reference parameter).

See boost next/prior at:

http://www.boost.org/doc/libs/1_39_0/libs/utility/utility.htm#functions_next_prior

Jeff

--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Daniel Krügler on 7 Apr 2010 05:58
On 7 Apr., 18:50, itaj sherman <itajsher...(a)gmail.com> wrote:
> Is there some standard/boost equivalent to a function like:
>
> template< typename T >
> T successor( T r )
> {
> return( ++r );
> }
>
> That can be used when the return value of operator++() is needed but
> not the side effect (notice non reference parameter).
>
> I always feel the need when using iterators and need to peek the
> following element, or using reverse iterators
>
> template< typename Container >
> void foo( Container const& r )
> {
> for( Container::reverse_iterator aI( r.rbegin() ); aI != r.rend(); +
> +aI )
> {
> // use successor(aI).base() or
> Container::iterator const bI( successor(aI).base() );
> // use bI...
> }
> }

What you are looking for, is std::next which will be
part of the C++0x library. Additionally, it's counterpart
std::prev will also be provided.

HTH & Greetings from Bremen,

Daniel Kr�gler


--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Francis Glassborow on 7 Apr 2010 05:57
itaj sherman wrote:
> Is there some standard/boost equivalent to a function like:
>
> template< typename T >
> T successor( T r )
> {
> return( ++r );

why not
return r+1;


> }
>
> That can be used when the return value of operator++() is needed but
> not the side effect (notice non reference parameter).
>

--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

From: Daniel Krügler on 7 Apr 2010 07:52
On 7 Apr., 22:57, Francis Glassborow
<francis.glassbo...(a)btinternet.com> wrote:
> itaj sherman wrote:
> > Is there some standard/boost equivalent to a function like:
>
> > template< typename T >
> > T successor( T r )
> > {
> > return( ++r );
>
> why not
> return r+1;
>

It looks to me as if the OP intends to
potentially support non-random access
iterators as well. The indicated general
container function template foo would
then work for e.g. std::list or std::set
as well.

Greetings from Bremen,

Daniel Kr�gler


--
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
[ comp.lang.c++.moderated. First time posters: Do this! ]

 |  Next  |  Last
Pages: 1 2 3 4
Prev: const is an overrated concept that is a source of extra typing and maintenan
Next: performance of map in MSVC 10b2