5.1 Object-Oriented Designs
  5.1.1 Background
  5.1.2 Objects
  5.1.3 Classes and Instances
 5.2 Application Programming Interfaces (APIs)
  5.2.1 A Peek at Programmed Classes
  5.2.2 A Peek at Programming without Object-Oriented Support
  5.2.3 From Object-Oriented Designs to API’s
  5.2.4 Classes as Data Types