C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  switch case error          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message gouqizi.lvcha@gmail.com Guest Posted: Fri Sep 30, 2005 2:54 am    Post subject: switch case error Hi, All: I remembered that I met a compiler error before that says something like "cannot declare variable past a label", who know exectly of what the error is? For example: int c; switch (c) case 1: .... break; case 2: int x; break; Thanks rick Back to top davidrubin@warpmail.net Guest Posted: Fri Sep 30, 2005 3:17 am    Post subject: Re: switch case error [email]gouqizi.lvcha (AT) gmail (DOT) com[/email] wrote: Quote: Hi, All: I remembered that I met a compiler error before that says something like "cannot declare variable past a label", who know exectly of what the error is? For example: int c; switch (c) case 1: .... break; case 2: { int x; } break; Introduce a new scope. /david Back to top Victor Bazarov Guest Posted: Fri Sep 30, 2005 3:20 am    Post subject: Re: switch case error [email]gouqizi.lvcha (AT) gmail (DOT) com[/email] wrote: Quote: I remembered that I met a compiler error before that says something like "cannot declare variable past a label", who know exectly of what the error is? For example: int c; You forgot to initialise it or to assign anything to it... Quote: switch (c) { Quote: case 1: .... break; case 2: int x; break; case 3: ... and at this point, should 'c' be 3, the declaration of 'x' is bypassed by this case label. While 'x' should be visible, its declaration/definition isn't "executed". That's what is not allowed. To overcome it you need to surround the contents of the 'case 2' block with curly braces thus making it a compound statement: case 2: { int x; ... break; } V Back to top gouqizi.lvcha@gmail.com Guest Posted: Fri Sep 30, 2005 12:31 pm    Post subject: Re: switch case error Victor, "Some declaration is bypassed by some execution path" will cause what problem? It is quite strange. Rick Back to top Dan Cernat Guest Posted: Fri Sep 30, 2005 12:47 pm    Post subject: Re: switch case error [email]gouqizi.lvcha (AT) gmail (DOT) com[/email] wrote: Quote: Victor, "Some declaration is bypassed by some execution path" will cause what problem? It is quite strange. Rick That is why that is an error. The problem isn't the fact that "some declaration is bypassed by some execution path". The problem is that the variable whos declaration was bypassed is visible down the execution path. #include <iostream> int main() { int c = 0; std::cin >> c; switch(c) { case 1: int x = 0; ++x; break; case 2: ++x; // <-- the problem is here } return 0; } the spot I marked is part of the scope of x. the problem is that if c == 2, the declaration of x is never executed. HTH dan Back to top gouqizi.lvcha@gmail.com Guest Posted: Sat Oct 01, 2005 5:34 pm    Post subject: Re: switch case error Thanks. I got it. Rick. 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.