swap (vector overload)

[cegodica]

Hello everyone.

I have an unclear question as follows:
In the tutorial about swap function (vector overload):
Link here: http://www.cplusplus.com/reference/vector/vector/swap-free/
In the example:

// swap (vector overload)
#include <iostream>
#include <vector>

main ()
{
  unsigned int i;
  std::vector<int> foo (3,100);   // three ints with a value of 100
  std::vector<int> bar (5,200);   // five ints with a value of 200

  foo.swap(bar);

  std::cout << "foo contains:";
  for (std::vector<int>::iterator it = foo.begin(); it!=foo.end(); ++it)
    std::cout << ' ' << *it;
  std::cout << '\n';

  std::cout << "bar contains:";
  for (std::vector<int>::iterator it = bar.begin(); it!=bar.end(); ++it)
    std::cout << ' ' << *it;
  std::cout << '\n';

  return 0;
}

In line 11, is there is a mistake, instead of writing std :: swap (foo, bar), then write foo.swap (bar)?

Please help me. Thanks.

[Peter87]

Both work, but since the page that you link to is for the free (non-member function) version it would probably have been better to show it in the example instead of the swap member function (http://www.cplusplus.com/reference/vector/vector/swap/).