namespace boost
{

    template
    <
        class T,
        class CloneAllocator = heap_clone_allocator
        class Allocator = std::allocator<void*>
    >
    class ptr_deque : public ptr_sequence_adapter
                             <
                                T,
                                std::deque<void*,Allocator>,
                                CloneAllocator
                             >
    {

    public: //[element access](#element-access)T& operator[]( size_type n );
        const T& operator[]( size_type n ) const;
        T& at( size_type n );
        const T& at( size_type n ) const;

    public: //[modifiers](#modifiers)void push_front( T* x );
        template< class U >
        void push_front([_compatible-smart-ptr_](compatible_smart_ptr.html)<U> x );
        auto_type pop_front();

    public: //[pointer container requirements](#pointer-container-requirements)auto_type replace( size_type idx, T* x );
       template< class U >
       auto_type replace( size_type idx,[_compatible-smart-ptr_](compatible_smart_ptr.html)<U> x );
       bool is_null( size_type idx ) const;

    };

} // namespace 'boost'