|
|
|
|
|
|
|
To see that the member-variable protection imposed by a protected
derivation persists in classes derived from the subclass, suppose
that you define a refrigerator_car class to be a class derived from
the box_car class. Further suppose that the derivation is public or
protected. Then, if you define a display_height function in the
refrigerator_car class definition, that display_height
function can get at the height member variable declared in the
box class definition:
box <-- Height declared to be a public member variable
^
| <-- Protected derivation
|
box_car <-- Height member variable acts as though protected
^
| <-- Public derivation
|
refrigerator_car <-- Height member variable is accessible
to member functions