const method and return type

[Andrea Fontana]

Just another thought. If we have:

class B;
struct C;

class A
{
    void method() const { ... }
    B another_class;
    C a_struct;
}

B is just a reference to a object, so method() should not 
reassign it. The reference should be const, not the object 
itself. method() should be able to call mutable another_class 
methods. Am I wrong?

Instead "a_struct" is not a reference, so method() should not 
edit it, this makes sense. You can return a copy or a const ref 
of a struct-member



On Saturday, 14 December 2013 at 00:09:03 UTC, Andrea Fontana 
wrote:
> I read:
>
> Const Member Functions
> Const member functions are functions that are not allowed to 
> change any part of the object through the member function's 
> this reference.
>
> I'm not changing anything. Just returning it.
>
> Is this a try to avoid something like the following, then?
>
> ... B getter() const { return this.b; }
> ... void getter2() const { B var = getter(); 
> var.non_const_method(); }
>
> I don't think it's the right way, is it?
> getter2() shouldn't be allowed becouse var is a reference to 
> this.b, that's ok. But enforcing constness of return type IMHO 
> is wrong.
>
> Something like:
>
> void main()
> {
>    B value = myclass.getter();
>    b.non_const();
> }
>
> seems correct to me. Also this seems correct:
>
> void getter2() /*non-const*/ { getter().non_const_method(); }
>
>
>
> On Saturday, 14 December 2013 at 00:01:31 UTC, Adam D. Ruppe 
> wrote:
>> On Friday, 13 December 2013 at 23:46:14 UTC, Andrea Fontana 
>> wrote:
>>> class A
>>> {
>>>   auto getter() const
>>>   {
>>>       return property;
>>>   }
>>>
>>>   int property = 0;
>>>
>>> Why this method return "const int"?
>>
>> Inside getter, "this" is const. Due to transitive const, all 
>> the members through this are const too.
>>
>> So inside getter, property is a const int. The auto return 
>> value returns the *exact* type, thus const.