Re: vector of structs?

From:

"Brian Muth" <bmuth@mvps.org>

Newsgroups:

microsoft.public.vc.stl

Date:

Thu, 27 Apr 2006 13:52:44 -0700

Message-ID:

<u5pIJyjaGHA.4972@TK2MSFTNGP03.phx.gbl>

"Jason S" <jmsachs@gmail.com> wrote in message
news:1146169753.282126.207280@y43g2000cwc.googlegroups.com...

I've used map<T> and vector<T> and such before, where T is a simple
type, but am rather confused about the recommended way of doing it with
structures, especially ones that contain objects as a member. (Like
CComBSTR and CComPtr)

If I have

typedef struct {
short s;
MyClass obj;
CComPtr<something> p;
} X_t;

should I use vector<X_t> or vector<X_t*>? If the former, how do I
handle push_back() with a structure? If the latter, then don't I have
to allocate memory for X_t, in which case, what's the point of using
vector<>? And if I do choose to allocate memory for X_t, I can't just
use malloc/CoTaskMemAlloc(sizeof(X_t)*N), because then how will it
properly initialize the non-simple types contained in X_t like obj()
and p() which might have constructors?

If you use vector<X_t *>, then you need to add code to free the structs
before the variable goes out of scope. I tend to chose vect<X_t> for that
reason (unless the struct is VERY large).

However, you need to then add a copy constructor and assignment operator.
Brush off your C++ language book and look up those terms.

More explicitly, you need to define:

X_t::X_t(const X_t &x)

and

inside your struct, implement
void operator=(const X_t &);