C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  defining or not defining destructors          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message johny smith Guest Posted: Wed Jun 30, 2004 2:17 am    Post subject: defining or not defining destructors If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? thanks! Back to top Chris Johnson Guest Posted: Wed Jun 30, 2004 3:34 am    Post subject: Re: defining or not defining destructors johny smith <princetonharvard (AT) charter (DOT) net> wrote: Quote: If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? If the "simple class" does not have invariants; resource allocation, exception cleanup, or the potential to be derived later on, then generally speaking - no, you will not need to provide one. The best answer I could offer is to make sure you understand what the destructor is for rather than give a "general rule of thumb" guideline. This includes but is not limited to the constructor and most importantly the class itself. -- Chris Johnson ~ ~ :wq -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- Back to top E. Robert Tisdale Guest Posted: Wed Jun 30, 2004 4:17 am    Post subject: Re: defining or not defining destructors johny smith wrote: Quote: If I have a simple class with say a couple of integers only, is there any need for me to provide a destructor? class X { private: // representation int a, b; public: // . . . /* X& operator=(const X& x) { a = x.a; b = x.b; return *this; } X(void) { } X(const X& x): a(x.a), b(x.b) { } ~X(void) { } */ }; I *always* define the assignment operator, default constructor, copy constructor and destructor then /*comment*/ them out! This documents the fact that I did *not* forget them but allowed the compiler to supply them as recommended. Back to top Niels Dybdahl Guest Posted: Wed Jun 30, 2004 8:21 am    Post subject: Re: defining or not defining destructors Quote: If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? If you want to be able to derive a new class from that class and the new class might need a destructor, then you should add a virtual destructor. A simple destructor is not enough in that case ! Niels Dybdahl Back to top Richard Herring Guest Posted: Wed Jun 30, 2004 11:04 am    Post subject: Re: defining or not defining destructors In message <40e27803$0$184$edfadb0f (AT) dtext02 (DOT) news.tele.dk>, Niels Dybdahl <ndy (AT) fjern (DOT) detteesko-graphics.com> writes Quote: If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? If you want to be able to derive a new class from that class and the new class might need a destructor, .... and there is a possibility of deleting instances of the derived class through a pointer to the base class ... Quote: then you should add a virtual destructor. A simple destructor is not enough in that case ! -- Richard Herring Back to top Peter Koch Larsen Guest Posted: Thu Jul 01, 2004 11:32 am    Post subject: Re: defining or not defining destructors "johny smith" <princetonharvard (AT) charter (DOT) net> skrev i en meddelelse news:10e48mf5p4mb664 (AT) corp (DOT) supernews.com... Quote: If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? thanks! No need at all. In fact, even if the class contains more complex types there is still no need to write a constructor: class demo { std::string s; std::vector v; .... }; demo is a complex class where the two elements shown (s and v) does have "real" destructors - destructors that have a job to do (memory management in this case), but there is still no need to write your own constructor - the compiler generated destructor is just fine. My recommendation is that you code in a way so that you normally wont have to write any destructors at all. The only exception should be for classes that manage some resource in one way or another. This way, the default generated copy constructor and assignment operator will also be okay and one less source of error has been removed. Kind regards Peter Back to top Prateek R Karandikar Guest Posted: Thu Jul 01, 2004 8:59 pm    Post subject: Re: defining or not defining destructors johny smith wrote: Quote: If I have a simple class with say a couple of integers only is there any need for me to provide a destructor? thanks! If you don't write a dtor, the compiler will provide its own. If you are happy with the default, no need to write your own. -- -- Abstraction is selective ignorance. -Andrew Koenig -- -- Back to top Rufus V. Smith Guest Posted: Thu Jul 01, 2004 9:00 pm    Post subject: Re: defining or not defining destructors "Howard" <alicebt (AT) hotmail (DOT) com> wrote Quote: "Peter Koch Larsen" <pklspam (AT) mailme (DOT) dk> wrote ...and one less source of error has been removed. I'm scratching my head, trying to figure out how to remove one less source of error...? :-) -Howard LMAO! That's another one for the DNRC newsletter! Rufus Back to top Howard Guest Posted: Thu Jul 01, 2004 9:03 pm    Post subject: Re: defining or not defining destructors "Peter Koch Larsen" <pklspam (AT) mailme (DOT) dk> wrote Quote: ...and one less source of error has been removed. I'm scratching my head, trying to figure out how to remove one less source of error...? :-) -Howard Back to top Peter Koch Larsen Guest Posted: Fri Jul 02, 2004 8:51 am    Post subject: Re: defining or not defining destructors "Howard" <alicebt (AT) hotmail (DOT) com> skrev i en meddelelse news:C__Ec.173365$Gx4.173318 (AT) bgtnsc04-news (DOT) ops.worldnet.att.net... Quote: "Peter Koch Larsen" <pklspam (AT) mailme (DOT) dk> wrote ...and one less source of error has been removed. I'm scratching my head, trying to figure out how to remove one less source of error...? :-) -Howard Arghhh!! ;-) Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         C++Talk.NET Forum Index -> C++ language (comp.lang.c++) All times are GMT Page 1 of 1   Jump to: Select a forum C/C++----------------C LanguageC Language (Moderated)C++ Language (Moderated)C++ language (comp.lang.c++)C++ language, library and standards Non-English C/C++ Newsgroups----------------C++ (German)C++ (French)  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.