#include <vector>
#include <list>
#include <iostream>
#include <cassert>

using namespace std;


//both foo() and bar() try to do the same thing:
//print the first elemnt in c and append it to c.


template <typename Container>
void foo(Container &c)
{
  assert( !c.empty() );
  auto &head = *(begin(c));
  c.push_back(head);
  cout << head << endl;
}

template <typename Container>
void bar(Container &c)
{
  assert( !c.empty() );
  auto head = begin(c);
  c.push_back(*head);
  cout << *head << endl;
}

int main(int argc, const char *argv[])
{
  {//1
    vector<int> c{1, 2, 3, 4};
    foo(c);
  }

  {//2
    vector<int> c{1, 2, 3, 4};
    bar(c);
  }

  {//3
    list<int> c{1, 2, 3, 4};
    foo(c);
  }

  {//4
    list<int> c{1, 2, 3, 4};
    bar(c);
  }
  return 0;
}