Back to Basics Designing Classes (part 1 of 2) Klaus Iglberger, CppCon 2021 klaus.iglberger@gmx.de2 Klaus Iglberger C++ Trainer/Consultant Author of the C++ math library (Co-)Organizer Beck, TDD by Example)The Challenge of Class Design 10 Guideline: Design classes for easy change. Guideline: Design classes for easy extensions.Design Guidelines 11 Back to Basics: Class Design (Part ) const; 23 Using inheritance naively to solve our problem easily leads to … … many derived classes; … ridiculous class names; … deep inheritance hierarchies; … duplication between similar implementations

Back to Basics Designing Classes (part 1 of 2) Klaus Iglberger, CppCon 2021 klaus.iglberger@gmx.de2 Klaus Iglberger C++ Trainer/Consultant Author of the C++ math library (Co-)Organizer duplication to enable you to change everything in one place (the DRY principle). Guideline: Design classes for easy change.Data Member Initialization 24 struct Widget { Widget() : Widget(42) // Decisions 63 Guideline: Encapsulate design decisions (i.e. variation points). Guideline: Design classes for easy change.Qualified/Modified Member Data 64 Back to Basics: Class Design (Part 1) The Challenge

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . liv The VirtualBox shell lvi Classes (interfaces) lviii 12 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 11, Classes (interfaces), page lviii and chapter 236.3, Enumerations (enums), page cdxxviii – and available to client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4 The VirtualBox shell 30 5 Classes (interfaces) 32 5.1 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 5, Classes (interfaces), page 32 and chapter 6, Enumerations (enums), page 402 – and available to anyone who client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4 The VirtualBox shell 56 5 Classes (interfaces) 58 5.1 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 5, Classes (interfaces), page 58 and chapter 6, Enumerations (enums), page 428 – and available to anyone who client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . liv The VirtualBox shell lvi Classes (interfaces) lviii 12 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 11, Classes (interfaces), page lviii and chapter 236.3, Enumerations (enums), page cdxxviii – and available to client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2. Unit Testing Support Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3.2.4. Support Classes for Integration Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuration with Component Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Mixing XML, Groovy Scripts, and Component Classes. . . . . . . . . . . . . . .

5.1.1 Changes to Classes (Interfaces) . . . . . . . . . . . . . . . . . . . . . . 35 5.1.2 Changes to Enumerations . . . . . . . . . . . . . . . . . . . . . . . . . . 36 6 Classes (interfaces) 38 6 virtualization engine below. It is completely documented in this SDK Reference – see chapter 6, Classes (interfaces), page 38 and chapter 7, Enumerations (enums), page 423 – and available to anyone who client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4 The VirtualBox shell 52 5 Classes (interfaces) 54 5.1 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 5, Classes (interfaces), page 54 and chapter 6, Enumerations (enums), page 368 – and available to anyone who client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4 The VirtualBox shell 53 5 Classes (interfaces) 55 5.1 IAdditionsFacility . . . . . . . . . . . . . . . . . . . . . . . . . . . . virtualization engine below. It is completely documented in this SDK Reference – see chapter 5, Classes (interfaces), page 55 and chapter 6, Enumerations (enums), page 389 – and available to anyone who client code that uses the web service: a) For Java as well as Python, the SDK contains easy-to-use classes that allow you to use the web service in an object-oriented, straightforward manner. We shall refer