Re: References vs Pointers

Stephen M. Webb wrote:
> On 02/07/08 17:07, Jon Earle wrote:
>>
>> Now, I was under the impression that references were just a fancy word for
>> pointers, ie: a reference is an address of an object.  So, why can I not
>> assign the reference to a pointer variable?  Missing something, not sure
>> what.
>
> In C++, a reference is not just a fancy word for a pointer.  It's an entirely
> different beast with entirely different semantics.
>
> If you want to assign an rvalue (like the X parameter in your setval
> function)
> to the address pointer to by a pointer, you need to apply the "dereference"
> operator to obtain the desired lvalue.  Perhaps that's the source of your
> confusion?
>
> void setval(myclass obj, int& x)
> {
>   *obj.i = x;
> }
>
> Or, alternatively, depending on what semantics you desire,
>
> void setval(myclass obj, int& x)
> {
>   obj.i = &x;
> }
>
> In the first example, the value of "j" will be assigned to wherever mc.i
> points (in your code, this will invoke undefined behaviour and unleash
> starved lions on certain parts of PEI, or maybe crash).  In the second
> example, mc.i will contain the address of j.

So, the reference, as received by a function, looks and acts like a parameter
that was passed by value, but actually refers, or points to, the original
value?  In which case, I would need to treat it as if it were not a pointer
but a local parameter and apply the address-of operator to get the original
memory location?

(Lions in PEI... new movie idea, perhaps?  Lazy coder's sloppy code unleashes
some horrible chain of events upon an unsuspecting population?)

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