Questions about private data and other classes

[sjaguar13]

If I had a date class with the private data month, day, and year, and I had a base class A with children classes B, and C, how would I use the month from the date in B? I have a B, and C variable, but I didn't use A. I don't know if that makes a difference.

[galathaea]

Does the date class expose any methods for getting that data?

[stober]

Is this what you mean? If not, please post an example. If it is, then class A cannot access the private members of class base.

class base
{
public:
   base();
   ~base();
private:
   int day,month,year;
};


class A public base
{
public:
   A();
   ~A();
};

[sjaguar13]

class Date {
public:
   Date( int = 1, int = 1, int = 1990 );
   int getMonth();
private:
   int month;
   int day;
   int year;
};

int Date::getMonth()
{
	return month;
}

class A {
private:
int Blah1
Date Blah2

};

class B : public A {
public:
   B( const char *, const char *, double = 0.0, int = 0, Date = 0 );

}

B::B(...)
{
        Blah2 = DatePassedIn;

       if(Blah2.month = = Blah1 )
       {
              ............
        }
}

I need to get the integer from the one class that's not related at all, and the integer from the base class.

[Yale]

B cannot access Blah1 and Blah2 at all, unless public methods are provided by A.

The only possible way for B to get access to A's field without other being able to would be for A to have Blah1 and Blah2 protected.

[sjaguar13]

I made some public methods for A, but it still doesn't work. Well, the int Blah1 seems to work, but not the date. I have:

int A::getMonth()
	{ return Blah2.month; }

but it says I cannot access private data from Date. Should I have a public function, getMonth(), in the Date class? How would I call that from A, Blah2.getDate()?

[Yale]

Blah2's month field is private in Date.
So A cannot have access to it. For A to access Blah2's month you need a public method in Date, getMonth(), that return month (or this->month, to be more explicit). And A::getMonth call Blah2.getMonth() instead of Blah2.month.

Indeed, it might be more flexible to define a getDate() method

You still need A's public getMonth, otherwise you wouldn't be able to have access to Blah2 from B.