Check out example codes for "shift element to end of vector c++". It will help you in understanding the concepts better.

Code Example 1

template <typename t> void move(std::vector<t>& v, size_t oldIndex, size_t newIndex)
{
    if (oldIndex > newIndex)
        std::rotate(v.rend() - oldIndex - 1, v.rend() - oldIndex, v.rend() - newIndex);
    else        
        std::rotate(v.begin() + oldIndex, v.begin() + oldIndex + 1, v.begin() + newIndex + 1);
}

auto initial_pos = 1;
auto final_pos = 4;
move(some_vector, initial_pos, final_pos);

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