Return vector from function

I have two classes, the first that contains a vector and a get-method like this:

std::vector<mytype> const& MyClassA::getvector(std::vector<mytype>::iterator &it)
{
    it = this->myiterator;

    return this->myvector;
}

std::vector<mytype> myvector;
std::vector<mytype>::iterator myiterator;

and I have another class where I should use the vector:

MyClassB::myfunction()
{
    std::vector<mytype>::iterator it;
    std::vector<mytype> vector = MyClassA->getvector(it);

    if (it > vector.begin())
    {
        ....
     开发者_JAVA技巧   (--it)->dosomestuff();
        ....
    }
}

in the if I get a runtime exception: iterators incompatible. Why?

EDIT 1

void MyClassA::setvector(mytype myelement)
{
    this->myvector.push_back(myelement);
    this->myiterator = this->myvector.end() - 1;
}

---

You have made a copy of the vector in the calling code, and the iterator isn't valid because it's still pointing to the original vector.

You probably intended something like this:

const std::vector<mytype> & vector = MyClassA->getvector(it);

---

Since you return std::vector<mytype> _const_&, the type of its iterator is std::vector::const_iterator.

EDIT:

Ah yes, I'm wrong and Mark Ransom is right. I leave this answer here because of the discussion in the comments, which itself may be useful to someone else.