Re: Iterators and functors

From:
"Victor Bazarov" <v.Abazarov@comAcast.net>
Newsgroups:
comp.lang.c++
Date:
Tue, 6 Mar 2007 16:43:28 -0500
Message-ID:
<eskna1$4bu$1@news.datemas.de>
tryptik@gmail.com wrote:

I have a question about iterators. I have a container of functors
that operate on an std::string. The functors go something like this:

class Functor {
  std::string operator()(const std::string& s) {/*manipulate
string*/; return newString;}
};

Now, I want to call the functors on a string argument. I write
something like this:

std::vector<Functor> vec;

/*Omitted creation and push_back of a couple Functors */

std::vector<Functor>::const_iterator it = vec.begin();
std::vector<Functor>::const_iterator end = vec.end();

std::string arg("Test argument");

for(; it != end; it++)
  std::cout << *it(arg) << "\n"; //Why doesn't this work?


What do you mean by "doesn't work"? Does it compile?

Instead of using the de-reference operator '*', I have to write the
following:

  it->operator()(arg);

Can some kind soul explain to me why this is? I prefer the cleaner
syntax of the first statement.


Use

    (*it)(arg);

And read your favourite C++ book again about the precedence of operators.

V
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