problem with virtual methods

[SeBeQ]

Hi I have problem with code:

class Base {

    ...

    public:
        virtual const wchar_t *Me() const{
            return L"Base";
        }

        virtual bool IsMe(const wchar_t *me_char) final{
            if ( wcscmpi( me_char, Me() ) == 0) {
                return true;
            } else {
                return false;
            }
        }

        ...

    };

    class Child : public Base {

    public:

        virtual const wchar_t *Me() {
            return L"Child";
        }

    };

    Child obj;

    obj.Me(); -> show Child;

    obj.IsMe("Child") -> show false because Me in IsMe is Base

How I could get IsMe from Child not from base?

[Dy7SLyTq]

first on line 35 you shouldnt have a ; in the middle, secondly pretty sure final is a java keyword, with const being the c++ equivalent, thirdly if you want it ot return true, you need to rewrite it in child except Me() would return "Child". thats the advantage of virtual functions. if all of your methods dont share a name then they dont need to be virtual

[SeBeQ]

but is any chance to get method without rewrite function?

I must always write IsMe() in any child class when it is always the same code?

[ne555]

@OP: respect the prototype
You are adding a non-const version of Me() in the Child class.

@DTSCode: http://en.cppreference.com/w/cpp/language/final (nothing to do with const)

[Dy7SLyTq]

you dont have to, but if you want your code to return true, yes

[ne555]

@DTSCode: see the template pattern

[SeBeQ]

Oh I got it the problem is use the const keyword, many thanks for you.

I delete final and virtual from me IsMe, and i remove const from Me() and it works.

[Dy7SLyTq]

@ne555: sorry we posted at the same time so i didnt see your link. ill check it out now

[Dy7SLyTq]

is that c++11? never heard of it before (which doesnt say much unfortunately :p). so i thought he was doing something like

const int myfunc() const { ... }
and got javas final mixed up with our const

@op: sorry for misleading you tehn

[SeBeQ]

yes, it is c++11.

[o1vk4iN6]

if ( wcscmpi( me_char, Me() ) == 0) {
                return true;
            } else {
                return false;
            }

Redundant code...

return wcscmpi(me_char, Me()) == 0;

is equivalent.