void eraseEvenVectorElements (std::vector<int>* v)
{
    for(std::vector<int>::iterator it = v->begin(); it != v->end(); it++) {
        // be careful, at erasing "it" element, the vector is squeezed and "it" = (it+1),
        // so it should be incremented only once again
        v->erase(it);
    }
}