copy_vectors.cpp

#include <iostream>
#include <string>
#include <vector>

using namespace::std;

class B{

};

class A{
    public:
      int x;
      B &b;
      A(int x,B &b):x{x},b{b}{}
};

int main()
{
    B b;
    A a1{1,b}, a2{2,b};
    vector<A> va, vb;
    va.push_back(a1);
    vb.push_back(a2);
    va.insert(std::end(va), std::begin(vb), std::end(vb));
    return 0;
}