C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  pssible confusion about iterators          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message puzzlecracker Guest Posted: Wed Sep 28, 2005 9:27 pm    Post subject: pssible confusion about iterators let's say I have class A{}; vector<A*>::iterator ii; is it fair to assume that ii has a type of A* (given that ii is not invalidated)? and use it as A* a= *ii; what are other mean to extract tbe pointer from vector? thanks Back to top puzzlecracker Guest Posted: Wed Sep 28, 2005 9:32 pm    Post subject: Re: pssible confusion about iterators puzzlecracker wrote: Quote: let's say I have class A{}; vector<A*>::iterator ii; is it fair to assume that ii has a type of A* (given that ii is not invalidated)? and use it as A* a= *ii; what are other mean to extract tbe pointer from vector? thanks Any ideas why my google interface multi-posts.. anyway that is NOT what I mean... something even more intersting. class A{}; vector<A>::iterator ii=vec.begin(); .... A* a =&(*ii); is it allowed... Back to top Victor Bazarov Guest Posted: Wed Sep 28, 2005 9:38 pm    Post subject: Re: pssible confusion about iterators puzzlecracker wrote: Quote: class A{}; vector<A>::iterator ii=vec.begin(); ... A* a =&(*ii); is it allowed... It's not only allowed (for a valid 'ii'), it's the only way. An iterator is NOT a pointer, and usually there is no conversion between them. V Back to top puzzlecracker Guest Posted: Thu Sep 29, 2005 12:31 am    Post subject: Re: pssible confusion about iterators Victor Bazarov wrote: Quote: puzzlecracker wrote: class A{}; vector<A>::iterator ii=vec.begin(); ... A* a =&(*ii); is it allowed... It's not only allowed (for a valid 'ii'), it's the only way. An iterator is NOT a pointer, and usually there is no conversion between them. V I always suspicious about iterators and about their return values , having a believe that they actually return proxies instead of object :( Back to top Clark S. Cox III Guest Posted: Thu Sep 29, 2005 1:01 pm    Post subject: Re: pssible confusion about iterators On 2005-09-28 20:31:09 -0400, "puzzlecracker" <ironsel2000 (AT) gmail (DOT) com> said: Quote: Victor Bazarov wrote: puzzlecracker wrote: class A{}; vector<A>::iterator ii=vec.begin(); ... A* a =&(*ii); is it allowed... It's not only allowed (for a valid 'ii'), it's the only way. An iterator is NOT a pointer, and usually there is no conversion between them. V I always suspicious about iterators and about their return values , having a believe that they actually return proxies instead of object Some iterators do return proxies. However, vector's iterators are not among them. Given your definition of 'ii' above: (*ii) will always return a reference to an object of type A (assuming that vec is not empty), and &*ii will be a pointer to that referenced object. -- Clark S. Cox, III [email]clarkcox3 (AT) gmail (DOT) com[/email] Back to top red floyd Guest Posted: Thu Sep 29, 2005 5:57 pm    Post subject: Re: pssible confusion about iterators Clark S. Cox III wrote: Quote: Some iterators do return proxies. However, vector's iterators are not among them. What about std::vector<bool>? 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.