Re: inheritance headache....
* James Kanze:
On Feb 1, 2:12 pm, "Alf P. Steinbach" <al...@start.no> wrote:
* James Kanze:
On Jan 31, 11:12 pm, "Alf P. Steinbach" <al...@start.no> wrote:
* b...@blah.com:
class abstractDescription
{
AbstractTarget* create(AbstractDescription* desc)
{
desc->create();
}
}
It's clear what you mean, something like
struct AbstractDescription
{
virtual std::auto_ptr<AbstractTarget> create() const = 0;
};
How is it so clear? Normally, auto_ptr suggests that the caller
will be responsible for deleting the object.
Yes, that was the case.
How do you know? There was nothing in the original posting to
suggest it, and it's rather the exception, and not the rule.
On the contrary, from the original posting:
* bob@blah.com:
Now somewhere, actually EVERYWHERE in this legacy code I see
statements like this;
// semi pseudo with
abstractTarget* createTarget(abstractDescription* desc)
{
// shortcut pseudo code for dynamic cast< > ()
if ( desc is concreteDesc1)
{
return new concreteTarget1();
}
else if (desc is concreteDesc2)
{
return new concreteTarget2();
}
else
{
return 0;
}
}
Notice that no information about the created objects is retained.
Hence, as I figure it, the caller has the responsibility for destroying
them.
Cheers, & hth.,
- Alf
--
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