#include <iostream>
#include<vector>
#include<iterator>
#include<algorithm>
int main() {
std::vector<int> v1 ={1, 2, 5};
std::vector<int> v2 ={3,4};
std::vector<int> v3=v1;//will hold the new one
v3.insert(v3.begin()+2,v2.begin(),v2.end());
//To see the result
std::ostream_iterator<int> printer{std::cout, " "};
std::copy(v3.begin(),v3.end(), printer);
}