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NNTP-Posting-Date: Tue, 12 Apr 2011 06:38:51 -0500
From: Pete Becker <pete@versatilecoding.com>
Organization: Roundhouse Consulting, Ltd.
Newsgroups: comp.lang.c++
Date: Tue, 12 Apr 2011 07:38:51 -0400
Message-ID: <2011041207385159183-pete@versatilecodingcom>
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Subject: Re: // how can I access A::a?
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Xref: x330-a1.tempe.blueboxinc.net comp.lang.c++:3462

On 2011-04-11 18:52:40 -0400, dick said:

>         /* multi_level_inheritance.cpp */
>         struct A
>         {
>             int a;
>         };
> 
>         struct B1 : public A
>         {
>             int a;
>         };
> 
>         struct B2 : public A
>         {
>             int a;
>         };
> 
>         struct C : public B1, public B2
>         {
>             int a;
>         };
> 
>         int main()
>         {
>             C ccc;
> 
>             ccc.a=123;
> 
>             ccc.B1::a=456;
> 
> /* 0030 */  ccc.B1::A::a=789;
> 
>         }
> 
> // c++ multi_level_inheritance.cpp
> // multi_level_inheritance.cpp: In function int main():
> // multi_level_inheritance.cpp:30: error: A is an ambiguous base of C
> 
> 
> // how can I access A::a?

There are two A::a's, which is why the error message said that the 
reference to A is ambiguous. You need to decide which one you want to 
access, then name it. Hint: there's one in B1 and one in B2.

-- 
  Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The 
Standard C++ Library Extensions: a Tutorial and Reference 
(www.petebecker.com/tr1book)