Explain why a subclass's CIR format should begin by matching the CIR
format of its superclass.
Solution
The code for an instance method is fixed to match the CIR format of the
class. A subclass can inherit the instance method, but the compiler will
not generate new code for the subclass. Thus, the code for this
inherited method is shared by the superclass and the subclass. Since
this generated code will expect instance variables to be located in
the CIR as in the superclass's CIR format,
the subclass's CIR format should begin by matching this format
in order for subclass instances be compatible with this existing code.