Inheritance Usage Ratio (IUR)
Description:
The IUR metric is a metric defined between a subclass and
one of its ancestor classes. It is the relative number of
inheritance-specific members from the ancestor class used in the
derived class.
A member of an ancestor class is an
inheritance-specific member if its usage is related to inheritance.
We identify the following inheritance-specific members:
- protected data members and methods;
- non-private virtual methods.
The IUR is computed by counting the number of inheritance-specific
members of the ancestor class that are used in the subclass, and then
divide it by the total numbers of inheritance-specific members
from the ancestor. The only usages that are counted are: the access of
protected data members, the call of protected methods and the redefinition
of a virtual method.