Michael,
The compiler can't decide whether to cast abc to a const char * and
then apply [] or use the [] function you provided. To fix, either
cast 0 to unsigned, or change the argument of your [] function to take
an int instead of an unsigned.
I'm not sure how this relates to the standard.
On Fri, Sep 24, 2010 at 2:01 PM, Michael Gong <gongweigang@xxxxxxxxx> wrote:
> Hi,
>
> I have following program:
>
> class A
> {
> public:
>
> A(const char * a);
>
> operator const char*() const {return data_;} //the
> error message will go away if removing this line
>
> char& operator[](unsigned int);
>
> protected:
> private:
> char* data_;
> };
>
>
> int main() {
> A abc("kkk");
> abc[0] = 'x';
> //this is the line causing the error message
> return 0;
> }
>
>
> If I compile with g++, it has following error message:
>
> ISO C++ says that `char& A::operator[](unsigned int)' and
> `operator[]' are ambiguous even though the worst conversion for the
> former is better than the worst conversion for the latter
>
> But when I compile it using SunStudio compiler, it works.
>
> I am not quite familar with ISO C++. Could anyone explain where the
> ambiguous come from ?
>
> Thanks.
>
> Michael
>
--
Andrew Bell
andrew.bell.ia@xxxxxxxxx
