templated operator()<<

as I understand things, the operator<<() needs to be external as to the
class and then declared as a friend of the class. I'm not sure if I
understand why that is the case.

I did this with a class called MESSAGE and had not trouble with the
general implementation. However, when I tried to do this with a
templated class that generally looks like, although this is not compiling

namespace stats{

   template<class T>
   class Distribution {
    template<T> friend std::ostream & operator<<(std::ostream &, const Distribution<T>&);
    public:
        /* ==================== LIFECYCLE ======================================= */
        Distribution (T descr, int occurances = 0);
        Distribution():freq(NULL),occurances(NULL){};
    // Distribution ( const Distribution &other ); /* copy constructor */
// ~Distribution (); /* destructor */
        /* ==================== ACCESSORS ======================================= */
        T description(){ return freq;}
            int population() { return occurances; }
        /* ==================== MUTATORS ======================================= */
        void increase_occ(){ ++occurances; std::cout << "description " << freq << " occurances " << occurances << std::endl; }
        void descrease_occ(){ --occurances; }
        /* ==================== OPERATORS ======================================= */
        //Distribution& operator = ( const Distribution &other ); /* assignment operator */
        int operator()(){
           return freq;
        }
        bool operator==(Distribution &tmp){
           if(this->freq == tmp.freq)
              return true;
           return false;
        }

        bool operator<(Distribution &tmp){
           if(freq < tmp.freq)
              return true;
           return false;
        }

    protected:
        /* ==================== DATA MEMBERS ======================================= */
    private:
        /* ==================== DATA MEMBERS ======================================= */
        T freq; //description of how many times found in a List
        int occurances; //description of how many times a frequency was found in a list
}; /* ----- end of class Distribution ----- */

template<typename T>
std::ostream & operator << ( std::ostream & os, const Distribution<T> & obj )
      {
     T desc = obj.description();
     int pop = obj.population();
     os << "The Identification of " << desc << " was seens " << pop ;
     return os;
      } /* ----- end of function operator << ----- */

Not this is not compiling because:

test_del.cpp|90| error: passing ???const stats::Distribution<int>??? as ???this??? argument of ???T stats::Distribution<T>::description() [with T = int]??? discards qualifiers

which is on the call for the use of the << operator on the class. before I templated
the operaotr<<(), I got a warning that I was using a non-templated function. I've done some research and this
peoblem seems to have been common, but I don't know of any solutions, and I don't understand what the implementation
issue is.