Re: Help needed for STL ifstream class

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Sat, 6 Oct 2007 00:52:48 -0400

Message-ID:

<fe74b3$8hv$1@news.datemas.de>

Kira Yamato wrote:

On 2007-10-05 22:20:13 -0400, "Victor Bazarov"
<v.Abazarov@comAcast.net> said:

Kira Yamato wrote:

I've posted this in another thread, but I suppose I should've
started a new thread for it instead.

I cannot get the following short program to compile under g++:

#include <iostream>
#include <fstream>
#include <iterator>
#include <algorithm>

using namespace std;

int main(int argc, char **argv)
{
copy(istream_iterator<char>(argc >= 2 ? ifstream(argv[1]) : cin),

'istream_iterator's constructor that accepts a stream object takes
the argument by non-const reference. A non-const reference cannot
be bound to a temporary.

I see. So in C++, temporary variables are always treated as const?

No. There is no connection. A non-const reference cannot be bound
to a temporary. But a temporary is not a constant object.

If so, is there a good reason why the C++ designer chose it this way?

It isn't so.

As far as I know, a temporary object lives on the stack, and there
should be no reason why it should not be modified.

Where they live is unspecified.

V
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