Re: oo design question

Maybe my explanation was not clear enough.
Let me describe again what I want to do.

There are 4 classes, P, A, B1 and B2.

class P;
class A;
class B1;
class B2;

P "has a" A pointer.
B1 and B2 "is a" A. (i.e. B1 and B2 are the derived classes from A)

class P
{
  public:
    P( bool b );
    void update(double t);
  private:
    A* _a1P;
    A* _a2P;
};

Here it is assumed that (*_a1P) and (*_a2P) are the same class objects
e.g. if _a1P is the pointer of B1, then _a2P too.

P::P( bool b )
{
  if( b )
 {
   _a1P = new B1();
   _a2P = new B1();
 }
 else
 {
  _a1P = new B2();
  _a2P = new B2();
 }
}

void P::update(double t)
{
  A& a1 = *_a1P;
  A& a2 = *_a2P;

  a1 += a2 * t;
}

How can you do "a1 += a2 * t" by operator overloading ?
operator+=() is easy because the returned value is not object
but reference. However, operator*() is not because it requires
copied object.
That's the reason why I posted this question here.
Do you think that this still doesn't make sense?

On Sun, 18 May 2008 10:20:51 -0400, Daniel T. wrote: