We are interested in providing a class, say class A, with an overloaded operator << for output. You can’t put a using directive or declaration in a function header. There are three ways to make namespace names available in a declaration of an overloaded operator<< Give two of the three ways to declare an overloaded operator << Give the #include, assume that class A has been defined, then define a stand-alone operator<< function for output of a class. Only give the two declarations, not the implementation, of such overloaded functions.

Question

What will be an ideal response?

Answer 1

An answer that qualifies
```
ostream
#include
// assume class A has been defined
std::ostream& operator<<(std::ostream& outStr,
const A& ObjectOut);
```
This answer makes only the name ostream available using declaration:
```
#include
// assume class A has been defined
using std::ostream;
ostream& operator<< (ostream& outStr,
const A & ObjectOut);
```
Yet another that uses a using directive is:
```
#include
// assume class A has been defined
using namespace std;
ostream& operator<< (ostream& outStr,
const A & ObjectOut);
```