Bridge

The bridge pattern has a hierarchy of abstraction classes 
(not abstract classes) access implementation classes through 
a hierarchy of implementation interfaces that parallels the 
abstraction hierarchy. Also, a one (abstraction class) to 
many (implementation) relationship is allowed for multiple 
implementations of any abstraction.

 
Implementing this pattern is weird because of the following
C++ constraint.


In C++ a class cannot inherit an interface implementation.

By this I mean, given the following classes
NOTE: The methods are inlined
-----------------------------------------------------
class A
{
public:
  void method_A(){};
};
-----------------------------------------------------

Another class 
-----------------------------------------------------
class B
{
public:
  void method_B(){};
};
-----------------------------------------------------

Here is the Interface.
-----------------------------------------------------
class I_AB 
{
virtual void method_A() = 0;
virtual void method_B() = 0;
};
-----------------------------------------------------


This class inherits from A and B and I_AB
-----------------------------------------------------
class C : public A, B, I_AB
{
};
-----------------------------------------------------

If you try and instantiate an obect of type C
This will give the error: 

cannot declare variable `cObject' to be of type `C'
because the following virtual functions are abstract:
virtual void I_AB::method_A()
virtual void I_AB::method_B()