12.3.1. Invoking Base-Class Functions from Derived-Class Objects
The example in Fig. 12.1 reuses the final versions of classes
BasePlusCommissionEmployee from Section 11.3.5. The example demonstrates three ways to aim base- and derived-class pointers at base- and derived-class objects. The first two are natural and straightforward—we aim a base-class pointer at a base-class object and invoke base-class functionality, and we aim a derived-class pointer at a derived-class object and invoke derived-class functionality. Then, we demonstrate the relationship between derived classes and base classes (i.e., the is-a relationship of inheritance) by aiming a base-class pointer at a derived-class object and showing that the base-class ...