Schaum's Outline Series

CHAPTER 12 Object-Oriented Metrics 193
TC ¼ 7
Class is_client classes
B&B calendar, bedroom, customer, transaction
calendar reservation
bedroom reservation
customer reservation
transaction none
payment none
expense none
CF ¼ 7=42
12.3.4 POLYMORPHISM FACTOR
The polymorphism factor (PF) is a measure of the potential for polymorphism.
Let MoðCiÞ be the number of overriding methods in class i.
Let MnðCiÞ be the number of new methods in class i.
Let DCðCiÞ be the number of descendants of class i.
PTC i¼1 PF ¼
MoðCiÞ PTC i¼1½MnðCiÞ DCðCiÞŠ EXAMPLE 12.5
Calculate the polymorphism factor on the Cþþ code from Example 12.3.
Class Mn Mo DC
Ax(),y() none 2
B w(),z() y() 1
C v() none 0
PF ¼ 1=ð2 2 þ 2 1 þ 1 0Þ ¼1=6