Re: Default ctor, etc generated by compiler for structs?

From:
"BobR" <removeBadBobR@worldnet.att.net>
Newsgroups:
comp.lang.c++
Date:
Sat, 16 Jun 2007 00:59:02 GMT
Message-ID:
<qBGci.169270$p47.16035@bgtnsc04-news.ops.worldnet.att.net>
JohnQ <johnqREMOVETHISprogrammer@yahoo.com> wrote in message...

Are a default constructor, destructor, copy constructor and assignment
operator generated by the compiler for a struct if they are not

explicitely

defined?


#include <vector>
struct Hmmm{ int mmm; };

{
std::vector<Hmmm> SVmmm(2);
std::vector<Hmmm> SVtwo;
SVtwo = SVmmm;
}

Can that work? Does it meet the requirements for a std container?
[ my tests say: yes, no problem, dude! ]
Now, add something non-simple to the struct, and test again.

I think the answer is yes, because "there is no difference between a

struct

and a class except the public/private access specification" (and a few

minor

other things). When I create a class, I always start by declaring the
default constructor, copy constructor and assignment operator private with
no implementation. I don't do that for structs though (I consider structs
like they were in C, but they really are not in the implementation as far

as

I know). I'm thinking that I don't handle structs the same because I trust
the compiler to do the right thing in the case of structs whereas bitwise
copy for a class may not be what is desired, for example.

Is the above reasoning OK? Should I continue NOT declaring/defining the
default stuff for structs?
John


class A{ public: int a;}; == struct A{ int a;};
class A{ int a;}; == struct A{ private: int a;};

Or did I misunderstand something (again!).

--
Bob R
POVrookie

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