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[QUOTE="Tom Smith, post: 2582387"]
I'm writing my own smart pointer class (as an exercise, not for real life use); 
I've got it to a point where I think it's usable: but I'm not quite sure. Any 
comments on the class gratefully received.

Cheers - Tom

/** code starts here **/
/**                  **/
/** obviously !      **/

#include <map>

template <class T> class ptr
{
   public:
     inline ptr() : t(null_t) { };
     inline ptr(ptr<T> const& other) : t (other.t)
       { Count[t]++; }
     inline ptr(T* const t2) : t (t2)
       { Count[t]++; }
     inline ~ptr()
       { Count[t]--; if (Count[t]==0 && t != null_t) delete t; }
     ptr<T> operator= (T* const t2)
       { Count[t]--; if (Count[t]==0 && t != null_t) delete t; Count.erase(t); t 
= t2; Count[t]++; }
     ptr<T> operator= (ptr<T> const& other)
       { Count[t]--; if (Count[t]==0 && t != null_t) delete t; Count.erase(t); t 
= other.t; Count[t]++; }
     bool operator== (ptr<T> const& other)
       { return (t == other.t); }
     bool operator== (T* const t2)
       { return (t == t2); }
     T* operator-> () { return t; }
     operator T* () { return t; }
     T* operator() (){ return t; }
   private:
     T* t;
     static std::map<T*, int> Count;
     static T* const null_t;
};

template <class T> std::map<T*, int> ptr<T>::Count;
template <class T>  T* const ptr<T>::null_t = 0;
[/QUOTE]

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