Using std::for_each

Quite often (right now actually), I have to do this...

Code:

std::container::const_iterator ci;
for (ci = my_container.begin(); ci != my_container.end(); ++ci) {
   std::cout << *ci;
}

I would like to use for_each for snippets like this, but can't figure out the syntax. Something like this?

Code:

std::for_each( my_container.begin(); my_container.end(); std::cout.operator<<() );

Nice try. No, you have to write a function or a functor that does the output and give it to for_each. The lesson here is that for_each is dumb and you're better off just ignoring it if you don't already have a function that fits the third argument.

In this case, std::copy may be more appropriate, for a container of some type T:

Code:

std::copy(my_container.begin(), my_container.end(),
          std::ostream_iterator<T>(std::cout));

In the next standard there will be tools that make for_each type stuff easier so you don't have to write a functor. Boost already has some stuff for that, although I believe it will be better when it is part of the language.

Yeah, I would recommend boost.