"mimi" <cainiaodelixiang@gmail.com> wrote in message
news:1179304180.251436.257130@k79g2000hse.googlegroups.com...
: It seems that iterator could be treated as the pointer to object. But
: I am quite doubt about it.
: Is using &(*iterator) instead of the pointer to object(after copy the
: object from the iterator) permitted, or appreciated?
:
: #include <vector>
:
: int main()
: {
: std::vector<int> vecFoo(4, 0);
: std::vector<int>::iterater iter = vecFoo.begin();
:
: //Some function need a pointer to int, should i use
: someFunc( &(*iter)); //(1)

This will work for (almost*) all iterators for accessing (only)
the item pointed to by the iterator.
In the case of a vector<>::iterator *only*, you can even index
the resulting pointer to access adjacent items (within the
bounds of the vector). E.g. someFunc( (&*iter)+1 ) will
be the same as &vecFoo[1].

* Some exceptions and caveats:
- istream_iterator: the * operator will return a temporary
object. While it will be possible to access its address,
the temporary object will only be valid until the
completion of the statement.
- An item class could overload the address-of operator (&)
in and unexpected way, but this would probably cause other
failures anyway.

On 5/16/2007 10:29 AM, mimi wrote:

It seems that iterator could be treated as the pointer to object. But
I am quite doubt about it.
Is using &(*iterator) instead of the pointer to object(after copy the
object from the iterator) permitted, or appreciated?

#include <vector>

int main()
{
std::vector<int> vecFoo(4, 0);
std::vector<int>::iterater iter =3D vecFoo.begin();

//Some function need a pointer to int, should i use
someFunc( &(*iter)); //(1)

//Should i use the following to replace the (1)
int i =3D *iter;
someFunc(&i);

return 0;
}

Thanks for any advice.

Use:

someFunc(&vecFoo[0]);

(see: Effective STL, Item 16)

S.
--
Stefan Naewe
stefan dot naewe at atlas-elektronik dot com- =D2=FE=B2=D8=B1=BB=D2=FD=D3=

- =CF=D4=CA=BE=D2=FD=D3=C3=B5=C4=CE=C4=D7=D6 -