C++Talk.NET

Dhruv · Guest

I was wondering whether if containers like auto_ptr<> can be designed and
used, because I have frequently required such functionality, and upto now,
I've been using a combination of the standard containers, and
boost::shared_ptr, but shared_ptr does have it's own overhead, and
efficiency glitches, so why not have a container that does exactly what
auto_ptr does? Manage memory........... So, it can destroy it's elements
when it it's scope is over, and also the basic iterators work like a
normal container, so that the client does not have to dereference then
while using. Makes the code neater.

I have here a rough sketch of what I have in mind. Any suggestions are
most welcome....... The begin(), end(), front(), back(), and all forms of
erase need to be overridden. Right now, I have only overridden the dtor to
show what use this container can be of. Also, the iterators will have to
be rewritten as shown, to change the behaviour of operator*, and
operator->.

//BEGIN CODE.

#include <vector>
#include <iostream>

namespace nstd {

template <class Type, class Allocator = std::allocator
class auto_vector : public std::vector<Type*, Allocator> {

typedef typename std::vector<Type*, Allocator> Base;

class ptr_iterator : public Base::iterator {
typedef typename Base::iterator Iterator_Base;

public:
ptr_iterator () { }
ptr_iterator (Iterator_Base IB_) : Iterator_Base (IB_) { }
Type& operator* () { return *Iterator_Base::operator*(); }
};

public:
typedef typename Base::value_type value_type;
typedef typename Base::const_reference const_reference;
typedef ptr_iterator iterator;
// void push_back (const_reference data)
// {
// std::cout<<"In the derived function"< // Base::push_back (data);
// }

iterator begin() { return static_cast ~auto_vector ()
{
typename Base::iterator rover = Base::begin ();
typename Base::iterator last = Base::end ();
while (rover != last) {
delete *rover;
++rover;
}
}
};
}

int main ()
{
nstd::auto_vector<int> avi;
avi.push_back (new int(23));
nstd::auto_vector<int>::iterator iter = avi.begin();
std::cout<<*iter;
}

//Container automatically destroyes the pointer's contents.

//END CODE.

Regards,
-Dhruv.

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Mirek Fidler · Guest

Dhruv · Guest

On Fri, 24 Oct 2003 21:16:54 +0000, Mirek Fidler wrote: