Re: reference type methods

From:
Ruben <ruben@www2.mrbrklyn.com>
Newsgroups:
comp.lang.c++
Date:
Mon, 14 Jul 2008 23:12:35 -0400
Message-ID:
<pan.2008.07.15.03.12.33.457530@www2.mrbrklyn.com>
On Mon, 14 Jul 2008 23:36:45 +1200, Ian Collins wrote:

Ruben wrote:

On Mon, 14 Jul 2008 23:26:07 +1200, Ian Collins wrote:

But I still am not sure why it doesn't cause a type mismatch error.


Because there isn't one.

The type of _array[index] is int. The function returns a reference to
an int, so there isn't any mismatch.


Thanks

That is the part I don't satisfactorly understand. Why is it not
returning the rvalue of the array element.


That would be const reference.

Why is it different than this

int x, y[10] = {1,2,3,4,5,6,7,8,9,10};

x = y[3];


How is it different? It is more like

int& x = y[3];

I would think the requested return value doen't match the method
definition and I'd have to return something like this

return &i[index];


No, you are out by one level of indirection. &i[index] takes the address
of i[index] and yields a pointer to int.


Yes but i[index] returns a literal integer. In fact, I don't know of any
way of returning a varriable, only the data that a symbolic variable
refers to.

I do know how to return an address of a variables assigned space, though a
pointer, like in scanf for example.

return i[index] isn't an lvalue. Yet when the fuction is defined as
returning a reference, it seems to have a seperate syntax unrelated to
the rest of a references implimentation. The only way I know of returning
an actually reference...actually I don't know a way because even under
this circumstance

int =y =3, z;
int & x = y;

z = x; //STILL an RVALUE assigned and copied to z

so

return x;//should still be an rvalue returned (unless you return a point)

This seems to be a seperate property of references.

Ruben

 

It looks like you should do some background reading on references and
pointers, particularly their differences.


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