C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  input stream state          C++Talk.NET Forum Index -> C++ Language (Moderated) View previous topic :: View next topic   Author Message f.anonymous@gmail.com Guest Posted: Mon Oct 24, 2005 9:10 am    Post subject: input stream state Hi, for an input stream s, can the expression: !s.bad() && !s.eof() && s.fail() ever be true? Thanks. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top kanze Guest Posted: Tue Oct 25, 2005 11:20 am    Post subject: Re: input stream state [email]f.anonymous (AT) gmail (DOT) com[/email] wrote: Quote: for an input stream s, can the expression: !s.bad() && !s.eof() && s.fail() ever be true? If only the failbit is set. Typically, this will be the case if there was a format error on input, e.g. you tried to read into an int, and the stream contained "abcd". (Note that in some cases of format error, it isn't 100% guaranteed that eof is not set. But this is about the closest you can come to detecting a format error.) -- James Kanze GABI Software Conseils en informatique orientée objet/ Beratung in objektorientierter Datenverarbeitung 9 place Sémard, 78210 St.-Cyr-l'École, France, +33 (0)1 30 23 00 34 [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top John Potter Guest Posted: Tue Oct 25, 2005 1:21 pm    Post subject: Re: input stream state On 24 Oct 2005 05:10:34 -0400, [email]f.anonymous (AT) gmail (DOT) com[/email] wrote: Quote: for an input stream s, can the expression: !s.bad() && !s.eof() && s.fail() ever be true? Sure. #include <cassert> #include <sstream> int main () { std::istringstream s("Fail"); int x; s >> x; assert(!s.bad() && !s.eof() && s.fail()); } John [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] Back to top f.anonymous@gmail.com Guest Posted: Wed Oct 26, 2005 1:18 pm    Post subject: Re: input stream state John Potter wrote: Quote: On 24 Oct 2005 05:10:34 -0400, [email]f.anonymous (AT) gmail (DOT) com[/email] wrote: for an input stream s, can the expression: !s.bad() && !s.eof() && s.fail() ever be true? Sure. #include <cassert #include int main () { std::istringstream s("Fail"); int x; s >> x; assert(!s.bad() && !s.eof() && s.fail()); } Ah, I see - thanks. So, does this condition only crop up on format errors? How about: template <typename input_stream> int test(input_stream &s) { char c; s.get(c); assert(!(!s.bad() && !s.eof() && s.fail())); } Can this assert ever fire? Thanks. [ See http://www.gotw.ca/resources/clcm.htm for info about ] [ comp.lang.c++.moderated. First time posters: Do this! ] 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 (Moderated) 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.