Re: How to pass STL containers (say a vector) ?
Daniel T. skrev:
[snip]
I think it is wrong to avoid iterators when working with beginners,
better iterators than bald pointers IMO. I also think it is wrong to
avoid templates in simple code like this (though I don't expect new
people to understand using them in Policy-Based Design situations.) If
however, I did want to avoid templates, I would still recommend iterator
based container passing. That way, at least the calling code will look
idiomatic.
I do not object to using iterators as such; rather I find it is better
to avoid these as the traps are many - e.g.
std::vector<...> v;
func(v.begin());
If the problem is to return a STL-container I thus still believe the
correct answer is to return it as you'd return an int - and NOT pass an
iterator to the container to avoid the expensive copy - oh but remember
to use an back_inserter and not just your plain begin() and end() ...
and also be sure that the container is empty so that you will return
the result properly and not append the result to whatever happens to be
in the container already. But watch out if your function could fail -
there might be some exception guarantees that you can now no longer
provide so perhaps you should create a temporary container and do a
swap after the call succeeds.
This level of detail is just plain wrong unless you are absolutely
confident that performance is going to suffer and that performance is
important.
We have a difference of opinion. I'll teach my way, you will teach your
way. When my students first come across code using the standard
algorithms they will think nothing of it.
I do not teach, but would surely advice any student of mine to use
<algorithm> whenever feasible.
/Peter