problems overloading outstream for custom ADT

Hi, I am doing a project where i make my own ADT, in this case a chemical compound. I am having problems overloading the << operator as a friend function and still being able to access private class variables. Any help would be appreciated, here is the code:

Compound.h

Code:

#include <iostream>
#include <string>
  
using namespace std;
  
class Compound{
  
  public:
         //constructors and accessors here

   friend ostream & operator<< ( ostream & os, const Compound & source );
  friend istream & operator>> ( istream & is, Compound & target );
  
 private:
           string name, ion;
           int protons, neutrons, electrons, weight, charge;
};
  
ostream & operator<< ( ostream & os, const Compound & source );
istream & operator>> ( istream & is, const Compound & target );

Compound.cc

Code:

#include "Compound.h"
#include <string>
  
using namespace std;

//all accessors/constructors done here

ostream & operator<< ( ostream & os, const Compound & source )
{
  os << source.name;
  return os;
}
 
istream & operator>> ( istream & is, const Compound & target )
{
  is >> target.name;
  return is;
}

The error

Code:

Compound.h: In function `std::istream& operator>>(std::istream&, const Compound&)':
Compound.h:44: error: `std::string Compound::name' is private
Compound.cc:147: error: within this context

Also, as you can see in my .h file i did 'using namespace std;'
My prof said not to use this but when I remove it nothing seems to work even though I also use it in the *.cc implementation file, mainly it says 'strings' arent a type even tho I #include <string>. Any suggestions here would be helpful as well. If more code is needed to see the problem let me know, thanks.
-alex

Try get ridding of the second declaration of << and >> that you have after you class. You already delcared them as friend in your class. That is enough.

Okay I tried removing the second 2 declarations of << and >> but I am still getting the same error. Would it have anything to do with the scope of namespace std? Everywhere I look it says I should stay away from using namespace std in header files but my strings won't work without it, could this also be part of my private variable problem?

Read carefully:

Code:

//declaration
friend ostream & operator<< ( ostream & os, const Compound & source );
friend istream & operator>> ( istream & is, Compound & target );

//implementation
ostream & operator<< ( ostream & os, const Compound & source )
istream & operator>> ( istream & is, const Compound & target )

Either remove const from the operator>> implementation paramater or add const to the operator>> declaration parameter.

edit:
Also, I would remove the "using namespace std;" and instead fully qualify the parts of the std namespace that you use. Example:

Code:

Compound.h
#include <iostream>
#include <string>
  
class Compound{
  
  public:
         //constructors and accessors here

   friend std::ostream & operator<< ( std::ostream & os, const Compound & source );
  friend std::istream & operator>> ( std::istream & is, Compound & target );
  
 private:
           std::string name, ion;
           int protons, neutrons, electrons, weight, charge;
};
  
std::ostream & operator<< ( std::ostream & os, const Compound & source );
std::istream & operator>> ( std::istream & is, const Compound & target );

... remove const from the operator>> ...

Do this, you don't want your variable to be const, if you make it const you won't be able to input a value into it.

I would still remove, the second declarations, they aren't needed, however if they match (parameter and type) then they shouldn't cause any problems being there.