We Are Interested in Providing a Class,say Class A,with an Overloaded

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.