Chapter Summary

An object has state, behavior, and identity
A class is a set of objects that share common structure (I.e., attributes) and common behavior (I.e., operations)
Every object is created as an instance of some class
- Its class “affiliation” does not change during its lifetime
- At any time, a class has zero or more instances
Classes are usually static
- Their existence, semantics, and relationships are defined before program execution
Objects are dynamic
- They can be created and destroyed during program execution
Hiding the implementation details of an object is called information hiding or encapsulation