embeded anonymous structs and unions...

embeded anonymous structs and unions...

[Gareth Pearce]

Hi,

I was wondering if there was someway to do the equivelent of what the 
following code looks like...

class Blah
{
    union
    {
        double coords[3];
        struct
        {
            double x, y, z;
        };
    };
}

that is, put an anonymous struct inside an anonymous union...
I tried the above with g++ 3.4 20030314 - with no luck...

the above combined with an operator[] returning a reference to coords 
elements
would allow
Blah c;
c.x = 1;
c.y = 1;
c.z = 1;
for (int i=0; i<3; i++)
    std::cout << c[i] << std::endl;

to function.

Any clues?

Thanks,
Gareth

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Re: embeded anonymous structs and unions...

[Eljay Love-Jensen]

Hi Gareth,

Try this...

class Blah {
public:
   double x,y,z;
   double& operator [] (int i) { return (&x)[i]; }
};

Note:  this is relying on the C++ behavior of laying out in memory the 
variables as given.  This is a typical (standard?) behavior of all the C++ 
compilers that I've used.

--Eljay