Класс контейнера, реализующий интерфейс

class ElemNotFound {};
 template < class ElemType, class IndexType > class IContainer
 {
 public:
 virtual const ElemType& GetElem( const IndexType& index ) const
throw ( ElemNotFound ) = 0;
 
 virtual void PutElem( const IndexType& index, const ElemType& elem )
 throw () = 0;
 };

template <class ElemType, class IndexType> class CContainer: public IContainer < ElemType, IndexType > 
{ 
private:
std::vector<ElemType> elems;
std::vector<IndexType> indexes;
 
public:
virtual const ElemType& GetElem( const IndexType& index ) const throw ( ElemNotFound ){
for(int i=0;i<elems.size();i++)
{ 
if((IndexType)indexes[i]==index) //перегрузка оператора == в IndexType
return elems[i]; 
}
throw ElemNotFound();
};
 
virtual void PutElem( const IndexType& index, const ElemType& elem ) throw (){
elems.push_back(elem);
indexes.push_back(index);
};
CContainer(){};
~CContainer(){};
};

bool operator==(IndexType index)
    {   
        return this->a==index.a;
    };

bool IndexType::operator == (const IndexType& index) const;