if Constructor can be used to initialize ...

[2005]

If a Constructor can be used to initialize, when is memory is allocated
/ say the "new" operator etc?

Thanks

[2005]

Alf P. Steinbach wrote:

* 2005:

You say "Sorry, that's incorrect." - Could you pls give explanations?

Yes, if you'd care to respect the conventions of the group¹: don't
top-post, don't quote signatures, quote only relevant things, but do
quote the relevant things, ask specific questions (about what you quoted
right above the specific questions), and use plain English.

Otherwise this could amount to a fullblown tutorial on basic C++.

And I've already written that² -- and besides, there isn't room enough
in a Usenet article.
Notes:
¹ In an earlier article in this thread, in reply to Kai-Uwe Bux' request
for the same, you wrote «Sorry about it - will follow it in the
future.», but you didn't.

Not True; Pls look at the time stamp.
I replied you before I replied to Kai-Uwe Bux' request - makes sense

² See the FAQ item titled «What other "newbie" guides are there for
me?», currently at <url:
http://www.parashift.c om/c++-faq-lite/newbie.html#faq-29.21>.

[2005]

Alf P. Steinbach wrote:

And I've already written that² -- and besides, there isn't room enough
in a Usenet article.
Notes:
¹ In an earlier article in this thread, in reply to Kai-Uwe Bux' request
for the same, you wrote «Sorry about it - will follow it in the
future.», but you didn't.
² See the FAQ item titled «What other "newbie" guides are there for
me?», currently at <url:
http://www.parashift.c om/c++-faq-lite/newbie.html#faq-29.21>.

Are you the author of "www.parashift. com" or
"www.parashift. com/c++-faq-lite/newbie.html#faq-29.21"?

Thanks

[Alf P. Steinbach]

* 2005:

Alf P. Steinbach wrote:

>* 2005:

>>You say "Sorry, that's incorrect." - Could you pls give explanations?

Yes, if you'd care to respect the conventions of the group¹: don't
top-post, don't quote signatures, quote only relevant things, but do
quote the relevant things, ask specific questions (about what you quoted
right above the specific questions), and use plain English.

Otherwise this could amount to a fullblown tutorial on basic C++.

And I've already written that² -- and besides, there isn't room enough
in a Usenet article.
Notes:
¹ In an earlier article in this thread, in reply to Kai-Uwe Bux' request
for the same, you wrote «Sorry about it - will follow it in the
future.», but you didn't.

Not True; Pls look at the time stamp.
I replied you before I replied to Kai-Uwe Bux' request - makes sense

Ah, well, sorry, I'll do a summary: look elsethread.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[Alf P. Steinbach]

* 2005:

Alf P. Steinbach wrote:

>And I've already written that² -- and besides, there isn't room enough
in a Usenet article.
Notes:
¹ In an earlier article in this thread, in reply to Kai-Uwe Bux' request
for the same, you wrote «Sorry about it - will follow it in the
future.», but you didn't.
² See the FAQ item titled «What other "newbie" guides are there for
me?», currently at <url:
http://www.parashift.c om/c++-faq-lite/newbie.html#faq-29.21>.

Are you the author of "www.parashift. com"

No, that's Marshall Cline.

or "www.parashift. com/c++-faq-lite/newbie.html#faq-29.21"?

Of the tutorial referred to there.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?

[Alf P. Steinbach]

* 2005:

You say "Sorry, that's incorrect." - Could you pls give explanations?

Alf P. Steinbach wrote:

>* Salt_Peter:

>>2005 wrote:
If a Constructor can be used to initialize, when is memory is allocated
/ say the "new" operator etc?

Thanks
You don't need the new operator to allocate - in a perfect world, using
new should be discouraged.

Sorry, that's meaningless.

>>A ctor's primary purpose is to allocate an instance based on the
contents of its type (ignoring inherited classes for now) and whatever
resources are required.

Sorry, that's incorrect.

In C++ constructors don't allocate memory for the object they're
constructing (they can allocate memory for members). The main purpose
of a C++ constructor is to couple initializion to object creation, so
that you can't have one without the other ("creation": that the object
becomes available for use). A simple static local variable is an
example where allocation in practice happens way long before the object
is created: the object is created the first time execution passes the
declaration, the memory for the object is reserved at program startup.

>>In C++ it happens to have a secondary purpose that is to initialize
members, if any, using an init list.

Sorry, that's incorrect.

See above.

>>The initialisation is not a
requirement but too often overlooked and quite usefull.

Sorry, that's incorrect.

See above.

>>To answer your question: allocation happens when the constructor is
invoked.

Sorry, that's incorrect.

See above.

>>and "invoke" does not mean "call".

Sorry, that's incorrect.

In the standard and common usage the terms "invoke" and "call" are used
interchangeably .

>>#include <iostream>

class N
{
int n;
public:
N() : n(0) { std::cout << "invoke ctor\n"; }
~N() { std::cout << "invoke d~tor\n"; }
const int& get() const { return n; }
};

int main()
{
N instance; // allocation happens here

Sorry, that's incorrect (although in practice true).

Formally the compiler is allowed to allocate memory for N any time
before the object is created ("created": becomes available for usage).

>> std::cout << "instance.n = " << instance.get() << std::endl;

return 0;
} // deallocation happens here - at end of scope

Sorry, that's incorrect (although in practice true).

See above.

>>/*
invoke ctor
instance.n = 0
invoke d~tor
*/

The explanation is in the FAQ:
http://www.parashift.com/c++-faq-lite/ctors.html

Sorry, that's incorrect (this FAQ section does not concern allocation,
and provides no explanation of when allocation occurs).

As said.

--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?