In this module you learned about the concept of polymorphism and why it is essential to designing code that requires little modification when functionality is added.
You learned:

1. What ad hoc polymorphism is and why it's useful
2. About the two types of ad hoc polymorphism: conversion and overloading
3. How to create special conversion member functions to convert from a user-defined type to a built-in type
4. How the compiler picks the appropriate version of an overloaded function