#include <iostream>
#include <utility>
#include <vector>

using namespace std;

struct POD {
  POD() { a = 2; }
  POD(int x) { a = x; }
  int a;
};

int
main(void)
{
  vector<pair<char,char> > a;
  pair<char,char> p = make_pair('a','b');
  a.push_back(p);
  vector<pair<char, char> > b(a);
  cout << b[0].first << endl;
  b[0].first = 'c';
  cout << b[0].first << endl;

  vector<POD> w;
  POD x; x.a=3;
  w.push_back(x);
  POD y(x);
  vector<POD> q(w);
  cout << q[0].a << endl;

  return 0;
}