How can I insert element into beginning of vector?

Question

I need to insert values into the beginning of a std::vector and I need other values in this vector to be pushed to further positions for example: something added to beginning of a vector and values moved from position 1 to 2, from 2 to 3 etc.

How can I do that?

Answer 1

Use the std::vector::insert function accepting an iterator to the first element as a target position (iterator before which to insert the element):

#include <vector>  int main() {     std::vector<int> v{ 1, 2, 3, 4, 5 };     v.insert(v.begin(), 6); } 

Alternatively, append the element and perform the rotation to the right:

#include <vector> #include <algorithm>  int main() {     std::vector<int> v{ 1, 2, 3, 4, 5 };     v.push_back(6);     std::rotate(v.rbegin(), v.rbegin() + 1, v.rend()); }