Re: design problem with inheritance

alessio211734 wrote:


You should pass class duck's private data to the methods defined in class
FlyBehavior as parameters. So, taking your example:

<code>
class FlyBehavior
{
     virtual void fly(DuckData &)=0;
}

class NoFly
    : public FlyBehavior
{
    virtual void fly(DuckData &){ std::cout << "couldn't fly" << std::endl;}
};

class duck
{
    DuckData data;

    FlyBehavior * bhv;
    void performFly(){ bhv->fly(data); }
}
</code>

Other things to note:
- as Noah Roberts already pointed out, this example is a rather poor use of
a strategy pattern. A much better example would be a class that implements
some sort of file output where the intended file format is set through a
strategy pattern.
- try to avoid printf() and the like in C++. It may not look like it, but
iostream is your friend.

Hope this helps,
Rui Maciel