Moving a vector element to the back of the vector

Question

Is there any better way (either faster or with fewer symbols of code) than erasing the element and re-adding it to the back?

template <typename T>
void moveItemToBack(std::vector<T>& v, size_t itemIndex)
{
   T tmp(v[itemIndex]);
   v.erase(v.begin() + itemIndex);
   v.push_back(tmp);
}

Answer 1

You can do this with std::rotate from the standard library. Since this doesn't change the vector size it also won't trigger a reallocation. Your function would look something like this:

template <typename T>
void moveItemToBack(std::vector<T>& v, size_t itemIndex)
{
    auto it = v.begin() + itemIndex;
    std::rotate(it, it + 1, v.end());
}