Move last element of vector<vector<int>> to beginning

Question

I need to move last element of vector<vector<int>> to beginning. I tried std::rotate , but it works only on integers. Also i tried std::move but I failed. How I can do this? Thank you in advance.

Answer 1

To place the last element at the beginning you can utilize the std::rotate function with reverse iterators . This performs a right rotation :

#include <iostream>
#include <vector>
#include <algorithm>

int main() {
    std::vector<int> v{ 1, 2, 3, 4, 5, 6, 7, 8, 9 };
    std::rotate(v.rbegin(), v.rbegin() + 1, v.rend());
    for (auto el : v) {
        std::cout << el << ' ';
    }
}

To swap the first and last element utilize the std::swap function with vector's front() and back() references:

std::swap(v.front(), v.back());

The std::rotate function is not dependent on the type.