last element of list

[xerix]

I'm trying to make a function which insert an object into a list and returns
an iterator to the new element in the list. But as far as I know there is no
function which returns an iterator to the last element of a list. (.end()
returns an iterator one item past the end of the list) How could I solve
this?

[Arne Adams]

Re: last element of list

"xerix" schrieb[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>
>[/color]
try std::list<T>::b ack() and make sure that your list is not empty

Arne

[Arne Adams]

Re: last element of list

"xerix" schrieb[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>
>[/color]
try std::list<T>::b ack() and make sure that your list is not empty

Arne

[xerix]

Re: last element of list


"Arne Adams" <inbox@arneadam s.com> wrote in message
news:c5918t$tso $06$1@news.t-online.com...[color=blue]
> "xerix" schrieb[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >
> >[/color]
> try std::list<T>::b ack() and make sure that your list is not empty
>
> Arne
>
>[/color]

back returns a reference to the last element from the list, but I need an
iterator to the last element of the list.

[xerix]

Re: last element of list


"Arne Adams" <inbox@arneadam s.com> wrote in message
news:c5918t$tso $06$1@news.t-online.com...[color=blue]
> "xerix" schrieb[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >
> >[/color]
> try std::list<T>::b ack() and make sure that your list is not empty
>
> Arne
>
>[/color]

back returns a reference to the last element from the list, but I need an
iterator to the last element of the list.

[Sander]

Re: last element of list

"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>[/color]
I don't know much about C++, but doesn't give end() an iterator to the
position where the next object will come? If so, you could first call end()
and then add the new object.

Sander

[Sander]

Re: last element of list

"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>[/color]
I don't know much about C++, but doesn't give end() an iterator to the
position where the next object will come? If so, you could first call end()
and then add the new object.

Sander

[xerix]

Re: last element of list


"Sander" <sander_ke@nosp am.hotmail.com> wrote in message
news:40780c0a$0 $41761$5fc3050@ dreader2.news.t iscali.nl...[color=blue]
> "xerix" <xerix@bla.nl > wrote in message
> news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >[/color]
> I don't know much about C++, but doesn't give end() an iterator to the
> position where the next object will come? If so, you could first call[/color]
end()[color=blue]
> and then add the new object.
>
> Sander
>
>[/color]

That ain't working either :(

[xerix]

Re: last element of list


"Sander" <sander_ke@nosp am.hotmail.com> wrote in message
news:40780c0a$0 $41761$5fc3050@ dreader2.news.t iscali.nl...[color=blue]
> "xerix" <xerix@bla.nl > wrote in message
> news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >[/color]
> I don't know much about C++, but doesn't give end() an iterator to the
> position where the next object will come? If so, you could first call[/color]
end()[color=blue]
> and then add the new object.
>
> Sander
>
>[/color]

That ain't working either :(

[Nick Hounsome]

Re: last element of list


"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>
>[/color]

list has bidirectional iterators so you can do end()-1

[Nick Hounsome]

Re: last element of list


"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list. But as far as I know there is[/color]
no[color=blue]
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>
>[/color]

list has bidirectional iterators so you can do end()-1

[John Harrison]

Re: last element of list


"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list.[/color]

The list<T>::insert function already returns an iterator to the newly
inserted element.
[color=blue]
> But as far as I know there is no
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>[/color]

Well I don't really see the connection between your two sentences, but if
you really want a function that returns an iterator to the last element of a
list then all you have to do is write one. Just use end() to get the one
past the end and then operator-- to move back to the end of the last.

template <class T>
list<T>::iterat or last_element(li st<T>& lst)
{
list<T>::iterat or i = lst.end();
return --i;
}

Of course bad things will happen if you use this function on an empty list.

john

[John Harrison]

Re: last element of list


"xerix" <xerix@bla.nl > wrote in message
news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=blue]
> I'm trying to make a function which insert an object into a list and[/color]
returns[color=blue]
> an iterator to the new element in the list.[/color]

The list<T>::insert function already returns an iterator to the newly
inserted element.
[color=blue]
> But as far as I know there is no
> function which returns an iterator to the last element of a list. (.end()
> returns an iterator one item past the end of the list) How could I solve
> this?
>[/color]

Well I don't really see the connection between your two sentences, but if
you really want a function that returns an iterator to the last element of a
list then all you have to do is write one. Just use end() to get the one
past the end and then operator-- to move back to the end of the last.

template <class T>
list<T>::iterat or last_element(li st<T>& lst)
{
list<T>::iterat or i = lst.end();
return --i;
}

Of course bad things will happen if you use this function on an empty list.

john

[xerix]

Re: last element of list


"Nick Hounsome" <nh002@blueyond er.co.uk> wrote in message
news:EjUdc.5707 2$Id.417@news-binary.blueyond er.co.uk...[color=blue]
>
> "xerix" <xerix@bla.nl > wrote in message
> news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >
> >[/color]
>
> list has bidirectional iterators so you can do end()-1
>
>[/color]

error C2784: 'ptrdiff_t std::operator -(const std::reverse_it erator<_RanIt>
&,const std::reverse_it erator<_RanIt> &)' : could not deduce template
argument for 'const std::reverse_it erator<_RanIt> &' from
'std::list<_Ty, _Ax>::iterator'
with
[
_Ty=int,
_Ax=std::alloca tor<int>
]

iter = listNum.end()--;

This isn't working either.
I'm using reverse iterators as a workaround, but that isn't actually what I
want.

[xerix]

Re: last element of list


"Nick Hounsome" <nh002@blueyond er.co.uk> wrote in message
news:EjUdc.5707 2$Id.417@news-binary.blueyond er.co.uk...[color=blue]
>
> "xerix" <xerix@bla.nl > wrote in message
> news:7fdae$4078 038b$d47f9535$1 9433@news.multi kabel.nl...[color=green]
> > I'm trying to make a function which insert an object into a list and[/color]
> returns[color=green]
> > an iterator to the new element in the list. But as far as I know there[/color][/color]
is[color=blue]
> no[color=green]
> > function which returns an iterator to the last element of a list.[/color][/color]
(.end()[color=blue][color=green]
> > returns an iterator one item past the end of the list) How could I solve
> > this?
> >
> >[/color]
>
> list has bidirectional iterators so you can do end()-1
>
>[/color]

error C2784: 'ptrdiff_t std::operator -(const std::reverse_it erator<_RanIt>
&,const std::reverse_it erator<_RanIt> &)' : could not deduce template
argument for 'const std::reverse_it erator<_RanIt> &' from
'std::list<_Ty, _Ax>::iterator'
with
[
_Ty=int,
_Ax=std::alloca tor<int>
]

iter = listNum.end()--;

This isn't working either.
I'm using reverse iterators as a workaround, but that isn't actually what I
want.