C++Talk.NET C++ language newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Why can't the source compile?          C++Talk.NET Forum Index -> C++ language (comp.lang.c++) View previous topic :: View next topic   Author Message sword Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Why can't the source compile? void test(int*& a); int main() { int a[4]; test(a); return 0; } Who can tell me the reason why the source above can't compile? I use VC++ 6.0. test.cpp(7) : error C2664: 'test' : cannot convert parameter 1 from 'int [4]' to 'int *& ' Back to top Mark P Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Re: Why can't the source compile? Phlip wrote: Quote: sword wrote: void test(int*& a); a is a reference to a pointer. That means you must pass a pointer, for the reference to seat on. int a[4]; test(a); a is not a pointer, it's an array. But it can decay to a pointer. The issue is that when it's viewed as a pointer, it's a constant pointer (i.e., it must point to the same place always). And you can't pass "T const" as "T&" since the constant qualifier is discarded someone may attempt to modify the T&. Rewrite the declaration of test as: void test( int* const& a ); and it should compile. -Mark Back to top Ian Collins Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Re: Why can't the source compile? sword wrote: Quote: void test(int*& a); int main() { int a[4]; test(a); return 0; } Who can tell me the reason why the source above can't compile? You can pass an array of int to a function with int* as its parameter, but there isn't an automatic conversion from an array of int to an int pointer reference. -- Ian Collins. Back to top Isold.Wang@gmail.com Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Re: Why can't the source compile? void test(int* a); int main() { int a[4]; test(a); return 0; } sword wrote: Quote: void test(int*& a); int main() { int a[4]; test(a); return 0; } Who can tell me the reason why the source above can't compile? I use VC++ 6.0. test.cpp(7) : error C2664: 'test' : cannot convert parameter 1 from 'int [4]' to 'int *& ' Back to top Phlip Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Re: Why can't the source compile? sword wrote: Quote: void test(int*& a); a is a reference to a pointer. That means you must pass a pointer, for the reference to seat on. Quote: int a[4]; test(a); a is not a pointer, it's an array. Either take out the & (most likely what you need), or introduce a pointer: int * p = a; test(p); And you might want to read ahead in your tutorial, to soak this stuff in... -- Phlip http://c2.com/cgi/wiki?ZeekLand <-- NOT a blog!!! Back to top sword Guest Posted: Wed Aug 23, 2006 9:10 am    Post subject: Re: Why can't the source compile? But if I write the function like this: void test(int* a); It will be OK. 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.