C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  what mean: const A&a = A() ?          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message Guest Posted: Sun Nov 12, 2006 9:12 am    Post subject: what mean: const A&a = A() ? hello, here is an example: in class vector explicit vector(size_type n, const T& val = T(), const A&a = A()):alloc(a) {...} vector I mentioned above is a constructor of a template class: template <class T, class A = allocator<T> > class vector{...}; so, I don't know what means = A(), because A is a typename here. Thank you very much. Back to top Andrey Tarasevich Guest Posted: Sun Nov 12, 2006 9:48 am    Post subject: Re: what mean: const A&a = A() ? nicknamenickname (AT) 126 (DOT) com wrote: Quote: ... so, I don't know what means = A(), because A is a typename here. Thank you very much. ... If 'A' is a type, 'A()' is an expression that evaluates to a default-initialized object of type 'A' (a _value_-initialized object of type 'A' in post-TC1 C++). For example, 'int()' evaluates to 0. 'double()' evaluates to 0.0. 'std::string()' produces a default-constructed temporary object of type 'std::string'. And so on. -- Best regards, Andrey Tarasevich Back to top Guest Posted: Sun Nov 12, 2006 10:10 am    Post subject: Re: what mean: const A&a = A() ? Thanks, that's very helpful "Andrey Tarasevich дµÀ£º " Quote: nicknamenickname (AT) 126 (DOT) com wrote: ... so, I don't know what means = A(), because A is a typename here. Thank you very much. ... If 'A' is a type, 'A()' is an expression that evaluates to a default-initialized object of type 'A' (a _value_-initialized object of type 'A' in post-TC1 C++). For example, 'int()' evaluates to 0. 'double()' evaluates to 0.0. 'std::string()' produces a default-constructed temporary object of type 'std::string'. And so on. -- Best regards, Andrey Tarasevich 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.