Перегрузка функций (Создать класс Set )

#include <iostream>
 
class TSet
{
   protected:
      struct TNode
      {
         int value;
         TNode* next;
 
         TNode(int value, TNode* next = NULL);
      };
      TNode* list;
 
      TNode*& Find(int value);
      void Push(int value);
 
   public:
      TSet();
      TSet(const TSet& set);
      TSet(const int* head, const int* tail);
      ~TSet();
 
      TSet& operator += (int value);
      TSet& operator -= (int value);
 
      friend TSet operator + (const TSet& first, const TSet& second);
      friend std::ostream& operator << (std::ostream& os, const TSet& set);
};
 
//-----------------------------------------------------------------------------
TSet::TNode::TNode(int theValue, TNode* theNext): value(theValue), next(theNext)
{
   ;
}
//-----------------------------------------------------------------------------
TSet::TSet(): list(NULL)
{
   ;
}
//-----------------------------------------------------------------------------
TSet::TSet(const TSet& set): list(NULL)
{
   const TSet::TNode* plist = set.list;
 
   for (; plist; plist = plist->next)
   {
      Push(plist->value);
   }
}
//-----------------------------------------------------------------------------
TSet::TSet(const int* head, const int* tail): list(NULL)
{
   for (; head <= tail; ++head)
   {
      (*this) += *head;
   }
}
//-----------------------------------------------------------------------------
TSet::~TSet()
{
   while (list)
   {
      TNode* node = list;
      list = list->next;
      delete node;
   }
}
//-----------------------------------------------------------------------------
TSet::TNode*& TSet::Find(int value)
{
   TNode** node = &list;
 
   for (; *node && ((*node)->value != value); node = &(*node)->next) { ; }
 
   return *node;
}
//-----------------------------------------------------------------------------
void TSet::Push(int value)
{
   TNode* node = new TNode(value, list);
   list = node;
}
//-----------------------------------------------------------------------------
TSet& TSet::operator += (int value)
{
   if (Find(value) == NULL)
   {
      Push(value);
   }
 
   return *this;
}
//-----------------------------------------------------------------------------
TSet& TSet::operator -= (int value)
{
   TNode*& node = Find(value);
 
   if (node)
   {
      TNode* removed = node;
      node = node->next;
      delete removed;
   }
 
   return *this;
}
//-----------------------------------------------------------------------------
TSet operator + (const TSet& first, const TSet& second)
{
   TSet result(first);
 
   const TSet::TNode* node = second.list;
 
   for (; node; node = node->next)
   {
      result += node->value;
   }
 
   return result;
}
//-----------------------------------------------------------------------------
std::ostream& operator << (std::ostream& os, const TSet& set)
{
   const TSet::TNode* node = set.list;
 
   for (; node; node = node->next)
   {
      os << node->value << ", ";
   }
   os << "\b\b ";
 
   return os;
}
//-----------------------------------------------------------------------------
 
int main()
{
   const int CDataForTest[] = {1, 2, 2, 3, 4, 5, 6, 6, 7, 7 ,7 , 8, 9, 10,
                               1, 2, 2, 3, 4, 5, 6, 6, 7, 7 ,7 , 8, 9, 10,};
 
   TSet first(CDataForTest, CDataForTest + 10);
   TSet second(CDataForTest + 10, CDataForTest + 20);
 
   first += 100;
   second += 200;
 
   first -= 2;
 
   std::cout << "first : " << first << std::endl;
   std::cout << "second : " << second << std::endl;
   std::cout << "first + second: " << (first + second) << std::endl;
 
   return 0;
}