Re: C++ References

From:

Rolf Magnus <ramagnus@t-online.de>

Newsgroups:

comp.lang.c++

Date:

Wed, 10 May 2006 13:48:46 +0200

Message-ID:

<e3sjuu$aki$01$1@news.t-online.com>

onkar wrote:

I want bi to be changed each time ai changes ,possibly using
references.Can anyone help me : bellow is the code - please suggest
changes -

Why do you have ai in the first place? Your A contains a B and can read bi's
value with get_bi(), so there is no need to have another variable that you
would have to keep consistent with it. You could make ai a reference, but I
don't really see an advantage in that.

#include<iostream>
using namespace std;
class B
{
        private:
                int bi;
        public:
                B()
                {
                        bi=10;
                }
                int& get_bi()
                {
                        return bi;
                }

The above function isn't very useful. Instead, you can simply make bi
public. The idea of accessor functions is that you can replace the internal
represenation without changing the interface, but that requires separate
get/set functions. With your verison, the representation can't be changed
anyway, so you can as well expose the member variable directly.

                void display()
                {
                        cout<<"bi = "<<bi<<endl;
                }
};
class A
{
        private:
                B b;
                int ai;
        public:
                A()
                {
                        ai=b.get_bi();
                }
                void assign(int i)
                {
                        ai=i;
                }
                void display()
                {
                        cout<<"ai = "<<ai<<endl;
                }
};
int main()
{
        B bo;
        bo.display();

        A ao;
        ao.display();
        ao.assign(1111);
        ao.display();
        bo.display();

        return 0;
}