Re: plain iterator to vector<const int>

From:
Barry <dhb2000@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 02 Oct 2007 15:59:28 +0800
Message-ID:
<fdt1df$m7r$1@news.cn99.com>
Ian Collins wrote:

Barry wrote:

t wrote:

Can you use a plain iterator to vector<const int> to write to it? It
doesn't seem like it should be possible, but Visual C++ 2005 Express
lets me:

vector<const int> vc;
vc.push_back(5);
vector<const int>::iterator iter = vc.begin();
*iter = 3; // compiles


Well,
element type used in standard container should be Assignable

/const int/ is not a model of Assignable.

Now, concept check is still not part of standard.
So this is not a bug.


I thought the first bug was accepting the the push_back.


I posted before I saw your post.

[code:
std::cout
      << typeid(std::vector<const int>::value_type).name()
      << std::endl;

std::cout
      << typeid(std::allocator<const int>::value_type).name()
      << std::endl;
--End-code]

MSVC8 produces:
int
int

that's why the code compiles.

[std:
20.4.1 The default allocator [lib.default.allocator]

template <class T> class allocator {
public:
....
typedef T value_type;
-- End-std]

So, actually allocator has a bug.

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