Re: String Iterators

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Wed, 18 Apr 2007 16:00:21 -0400
Message-ID:
<f05tcn$38r$1@news.datemas.de>
Adrian wrote:

I want a char * (not const) from a std::string.

I see string.begin() return an iterator which is implementation
defined.
And *iterator returns a reference to the element
So does &*iterator return a pointer to the element?


Yes.

Now this below compiles but is it legal?

Adrian

#include <iostream>
#include <string>
#include <locale>

int main(int argc, char *argv[])
{
  std::string mixed("We ARE a test String");

  const std::ctype<char > &ctype=std::use_facet<std::ctype<char >

(std::locale::classic());


  std::cout << mixed << std::endl;

  // What is a good way to get the pointer from an iterator
  // Are you allowed to do this?
  ctype.tolower(&*mixed.begin(), &*mixed.end());


This assumes that the string keeps its characters in an array. I
don't think this is guaranteed anywhere in the Standard. Why can't
you simply use 'transform'?

   std::transform(mixed.begin(), mixed.end(), mixed.begin(), tolower);

? Just curious. You can of course write your own 'tolower' that
would use your specific facet, can't you?

  std::cout << mixed << std::endl;

  // instead of this
  ctype.toupper(&mixed[0], &mixed[mixed.length()]);
  std::cout << mixed << std::endl;

  return 0;
}


V
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