Re: nested stl containers - aliasing stl objects without invoking operator=

From:

James Kanze <james.kanze@gmail.com>

Newsgroups:

comp.lang.c++

Date:

Thu, 22 Oct 2009 02:00:59 -0700 (PDT)

Message-ID:

<b9ac4e67-2298-42fe-9fa9-0998bab1810f@j9g2000vbp.googlegroups.com>

On Oct 21, 11:07 pm, Andrey Vul <andrey....@gmail.com> wrote:

On Oct 21, 3:42 am, James Kanze <james.ka...@gmail.com> wrote:

(You can, of course, write a thin wrapper class which
uses pointers in the array, but dereferences them in
operator[].)

Like this:

template <typename T>
class pvec {
private:
        vector<T> *p;
public:
        T& operator[](unsigned x) {
                return p->at[x];
        }
        pvec& operator=(vector<T> *p2) {
                p = p2;
                return *this;
        }
        pvec& operator=(pvec<T>& pv) {
                p = pv.p;
                return *this;
        }

        unsigned size() const {
                return p->size();
        }
};

?

Also, would boost::shared_ptr<vector<T>> be better than vector<T> * ?

It depends on what you're doing, but probably not. At any
rate, you couldn't implement the above interface using it. (But
for the moment, I'm not really sure what you're trying to do. I
don't see any advantage in using the above rather than simply
having a reference to the vector.)

--
James Kanze