Re: constructing vector<POD> that is member of a class from an input stream (file)

From:
red floyd <redfloyd@gmail.com>
Newsgroups:
comp.lang.c++
Date:
Tue, 17 Nov 2009 14:20:07 -0800 (PST)
Message-ID:
<29cb2584-b458-49d6-8721-3ecabec6fe4b@z7g2000vbl.googlegroups.com>
On Nov 17, 12:02 pm, "Hicham Mouline" <hic...@mouline.org> wrote:

Hello,

I have a text file with this format:

floating11 floating12 floating13 floating14
floating21 floating22 floating23 floating24
...
floatingN1 floatingN2 floatingN3 floatingN4

I have a simple struct

struct F {
  double d1;
  double d2;
  double d3;
  double d4;

};

and a
std::vector<F> v;

then a class C which adds intelligence to the processing of the vector of
Fs.
class C {
  C(const std::istream& input);
private:
  std::vector<F> v_;

};

I wish to construct an instance of C from a file.
I thought to use the iterator form of vector<F>'s ctor.

Do I write an iterator class that when dereferenced, points to an instanc=

e

of F, so that I can do

C::C(const std::istream& input)
: v_( begin, end )
{}

Was there a stream_iterator in std?

I understand there is some elegant form to fill up a vector as;
std::copy( ? , ? , v_.back_inserter() );

Is there a similar form for vector construction?


Use std::istream_iterator<>.
You need to define operator<< for F.

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