C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Why default constructor isn't enough?          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message Busin Guest Posted: Sun Jun 27, 2004 9:35 pm    Post subject: Why default constructor isn't enough? class AA { public: const int n; }; int main() { AA a; .... } This code gives error: "C2512: 'AA' : no appropriate default constructor available." Then adding a constructor fixes the error. class AA { public: const int n; AA(int m) : n(m) {} }; int main() { AA a(1); ... } Can someone elaborate why with a const member variable, the default constructor isn't enough? Thanks! Back to top Thomas J. Gritzan Guest Posted: Sun Jun 27, 2004 9:43 pm    Post subject: Re: Why default constructor isn't enough? Busin schrieb: Quote: class AA { public: const int n; }; Your const variable has to be initialized at construction time, because it could not be changed later. Thomas Back to top Ali Cehreli Guest Posted: Sun Jun 27, 2004 11:54 pm    Post subject: Re: Why default constructor isn't enough? On Sun, 27 Jun 2004 21:35:53 +0000, Busin wrote: Quote: class AA { public: const int n; }; int main() { AA a; ... } This code gives error: "C2512: 'AA' : no appropriate default constructor available." Then adding a constructor fixes the error. [...] Quote: Can someone elaborate why with a const member variable, the default constructor isn't enough? Thanks! What I understand from this is that a const member can only be initialized in the initialization list, which requires a constructor. Ali Back to top JKop Guest Posted: Mon Jun 28, 2004 10:06 am    Post subject: Re: Why default constructor isn't enough? Busin posted: Quote: Can someone elaborate why with a const member variable, the default constructor isn't enough? Thanks! Looks like you must initialize a const variable. -JKop Back to top Devesh Mandowara Guest Posted: Mon Jun 28, 2004 10:15 am    Post subject: Re: Why default constructor isn't enough? If there is an initialiser list...its enough -Devesh "JKop" <NULL (AT) NULL (DOT) NULL> wrote Quote: Busin posted: Can someone elaborate why with a const member variable, the default constructor isn't enough? Thanks! Looks like you must initialize a const variable. -JKop 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.