The last three libraries should be removed as they're not being used. There's no need to keep a library around if you're long longer using it or have never used even it.

You may also consider organizing them in some way, such as alphabetically.

You don't really need these:

using std::vector;
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::ostream_iterator;
using std::istream_iterator;

Just use std:: where needed, otherwise it'll just get longer if you add more. Also, you have listed using std::vector twice, but it should just be there once.

print() isn't modifying any data members (it just prints something):

print( std::vector<float> &data )

so data should be passed by const& to avoid an unnecessary copy:

  print(std::vector<float> const& data)

Using parentheses for a simple return is not really needed:

return ( 0 );

Just keep it simple and omit them:

  return 0;

Moreover, you don't really need this. Reaching the end of main() already implies success, so the compiler will insert the return itself.

The last three libraries should be removed as they're not being used. There's no need to keep a library around if you're long longer using it or have never used even it.

You may also consider organizing them in some way, such as alphabetically.

You don't really need these:

using std::vector;
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::ostream_iterator;
using std::istream_iterator;

Just use std:: where needed, otherwise it'll just get longer if you add more. Also, you have listed using std::vector twice, but it should just be there once.

print() isn't modifying any data members (it just prints something):

print( std::vector<float> &data )

so data should be passed by const& to avoid an unnecessary copy:

  print(std::vector<float> const& data)

There's no need to provide your own swap() function; just use std::swap:

  std::swap(lit, rit);

This is not a very common nor maintainable style in my_qsort():

if( lit > rit ) { break; }
else { lit++; }

Put each bracketed statement on its own line, in case you ever need to add to them:

  if (lit > rit) {
      break;
  }
  else {
      lit++;
  }

Why is there a "pause" in my_qsort()?

char c;
cin >> c;

Just let the function works without such interruptions. But if you must keep it anyway, then at least make the user aware that it's a pause, and tell them to input a character in order to continue.

Using parentheses for a simple return is not really needed:

return ( 0 );

Just keep it simple and omit them:

  return 0;

Moreover, you don't really need this. Reaching the end of main() already implies success, so the compiler will insert the return itself.

Since you're not using assertions, just remove <assert.h>.

You don't really need these:

using std::vector;
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::ostream_iterator;
using std::istream_iterator;

Just use std:: where needed, otherwise you'll just end up growing this list. Also, you have listed std::vector twice, but it should just be there once.

print() isn't modifying any data members (it just prints something):

print( std::vector<float> &data )

so data should be passed by const& to avoid an unnecessary copy:

  print(std::vector<float> const& data)

Using parentheses for a simple return is not really needed:

return ( 0 );

Just keep it simple and omit them:

  return 0;

Moreover, you don't really need this. Reaching the end of main() already implies success, so the compiler will insert the return itself.

The last three libraries should be removed as they're not being used. There's no need to keep a library around if you're long longer using it or have never used even it.

You may also consider organizing them in some way, such as alphabetically.

You don't really need these:

using std::vector;
using std::cin;
using std::cout;
using std::endl;
using std::vector;
using std::ostream_iterator;
using std::istream_iterator;

Just use std:: where needed, otherwise it'll just get longer if you add more. Also, you have listed using std::vector twice, but it should just be there once.

print() isn't modifying any data members (it just prints something):

print( std::vector<float> &data )

so data should be passed by const& to avoid an unnecessary copy:

  print(std::vector<float> const& data)

Using parentheses for a simple return is not really needed:

return ( 0 );

Just keep it simple and omit them:

  return 0;

Moreover, you don't really need this. Reaching the end of main() already implies success, so the compiler will insert the return itself.