C++ template-based friend operators

http://www.parashift.com/c++-faq-lite/templates.html#faq-35.16 describes two ways of solving the "call to non-template" error. This error gets thrown when one defines a template class with some friend operator(s) declared in a natural manner, not thinking that declaring the template friend(s) like this will resolve the method into a non-template one. I find the first method of pre-declaring the operator to be tiresome and the second i say it can make the class definition unreadable if the operator definition is complex. I'm going to choose a third way of defining template friends:

template <typename T>
class C
{
  template <typename T1> friend istream& operator>>(istream &, C<T1>&);
}

altho this can be a little bit hard to understand at first sight because of different template parameter name


update: example for jamie

#include <iostream>

using namespace std;

//we define 

//the ostream operator the parashift's way 

//and the istream operator deadloop's way

  

  

//ostream operator related code

template<typename T> class A;

template<typename T> ostream& operator<< (ostream &os, const A<T>& a) throw();

//for istream we don't need to predeclare anything

template<typename T>

class A

{

public:

  A();

  template <typename T1> A(T1 value) throw();

  virtual ~A();

  //this is deadloop's istream operator, i don't need to convince the

  //compiler of anything

  template <typename T1> friend istream& operator>> (istream &is, A<T1>& a) throw();

  //and the parashift's way

  friend ostream& operator<< <> (ostream &os, const A<T>& si) throw();

private: 

  T data;

};

template <typename T> A<T>::A() {}

template <typename T> A<T>::~A() {}

template <typename T> istream& operator>> (istream &is, A<T> &a) throw()

{ 

  is>>a.data;

} 

  

template <typename T> ostream& operator<< (ostream &os, const A<T>& a) throw()

{

  return os<<a.data;

}

int main(int argc, char **argv)

{

  A<int> ob;

  cout<<"enter an integer for A<int>: ";

  cin >>ob;

  cout << "object's data is: " << ob << endl;

  return 0;

}