vector v{1,2,3,4,5,6,7,8,9};

int rot = 2;
//rotate left
rotate(v.begin(), v.begin() + rot, v.end()); //vector: 3 4 5 6 7 8 9 1 2
//rotate right
rotate(v.begin(), v.begin()+v.size()-rot, v.end()); //vector: 8 9 1 2 3 4 5 6 7