Practical C++ Design

Go from competent C++ developer to skilled designer or architect using this book as your personal C++ design master class. Updated for the C++20 standard, this title will guide you through the design and implementation of an engaging case study that forms the backdrop for learning the art of applying design patterns and modern C++ techniques to create a high quality, robust application.

Starting with a quick exploration of the requirements for building the application, you'll delve into selecting an appropriate architecture, eventually designing and implementing all of the necessary modules to meet the project’s requirements. By the conclusion of Practical C++ Design, you'll have constructed a fully functioning calculator capable of building and executing on any platform that supports both Qt and C++20. Access to the complete source code will help speed your learning.

Utilize the Model-View-Controller pattern as the basis for the architecture of the calculator; the observer pattern to design an event system; the singleton pattern as you design the calculator’s central data repository, a reusable stack; the command pattern to design a command system supporting unlimited undo/redo; the abstract factory pattern to build a cross-platform plugin infrastructure for extensibility; coroutines to implement a command line interface with a lazy tokenizer; and more.

After reading and using this book, you’ll have begun the transition from C++ programmer to architect.

WHAT YOU WILL LEARN

* Read a specification document and translate it into a practical C++ design using some of the latest language features from C++20
* Understand trade-offs in selecting between alternative design scenarios
* Gain practical experience in applying design patterns to realistic development scenarios
* Learn how to effectively use language elements of modern C++ to create a lasting design
* Develop a complete C++ program from a blank canvas through to a fully functioning, cross platform application
* Read, modify, and extend existing, high quality code
* Learn the fundamentals of API design, including class, module, and plugin interfaces

WHO THIS BOOK IS FOR

The experienced C++ developer ready to take the next step to becoming a skilled C++ designer.

ADAM B. SINGER graduated first in his class at the Georgia Institute of Technology in 1999 with a bachelors degree in chemical engineering. He subsequently attended the Massachusetts Institute of Technology on a National Defense, Science, and Engineering Graduate Fellowship. He graduated from MIT with a Ph.D. in chemical engineering in 2004 after defending his thesis titled Global Dynamic Optimization. Since graduation, Adam has been a member of the research and engineering staff at an oil and gas major, where he has worked in software development, design, and project management in areas such as optimization, reservoir simulation, decision support under uncertainty, basin modeling, well log modeling, and stratigraphy. He has also served on and chaired committees designing in-house training in the areas of technical software development and computational and applied mathematics. He currently holds a research supervisory position. Adam additionally held the title of adjunct assistant professor in the Department of Computational and Applied Mathematics at Rice University from 2007-2012. In both 2006 and 2007, he taught a graduate level course, CAAM 520, on computational science. The course focused on the design and implementation of high performance parallel programs.

Preface (5 pages)

The preface details my motivation for writing the book, the target audience for the book, the

general structure of the book, and how to contact the author. Of particular importance is the

rationale behind choosing the case study, the target language (C++), and the GUI toolkit (Qt).

Chapter 1: Defining the Case Study (6 pages)

The first chapter describes, in detail, the case study to be examine in the book. The chapter

discusses requirements in the abstract and then transitions to the calculator’s specific requirements.

This sets the stage for the remainder of the book, which describes, in detail, the design and

implementation of the calculator, pdCalc, proposed in Chapter 1.

1. A Brief Introduction

2. A Few Words About Requirements

3. Reverse Polish Notation (RPN)

4. The Calculator’s Requirements

5. The Source Code

1The advice, information, and conclusions discussed in this book are those of the author and have not been

endorsed by, or reflect the opinions or practices of, ExxonMobil Corporation or its affiliates.

5

Chapter 2: Decomposition (18 pages)

In this chapter, I explain the elements of a good decomposition and strategies for decomposing a

problem into manageable pieces. Subsequently, an architecture for pdCalc is selected, the calculator

is modularized, and use cases are used to develop interfaces for the high level calculator modules.

The four high level modules are the stack, the command dispatcher, the user interface (subdivided

into a command line interface and a graphic user interface), and a plugin manager.

1. The Elements of a Good Decomposition

2. Selecting An Architecture

3. Interfaces

4. Assessment of Our Current Design

5. Next Steps

Chapter 3: The Stack (20 pages)

The stack is the first module discussed in detail. The stack is the fundamental data repository

of the calculator. As part of the calculator’s design and implementation, the singleton pattern is

explored. The stack also affords the first opportunity to discuss an event system for the calculator,

which provides a backdrop for exploration of the observer pattern, including the design and

implementation of reusable publisher and observer abstract classes.

1. Decomposition of the Stack Module

2. The Stack Class

3. Adding Events

4. A Quick Note on Testing

Chapter 4: The Command Dispatcher (32 pages)

This chapter describes the design and implementation of the command dispatcher, the module of

the calculator responsible for the creation, storage, and execution of commands. Of particular note

in this chapter is the exposition on the command pattern and how it can be used to implement a

practical undo/redo framework. In addition to exploring a traditional deep hierarchy method for

implementing commands, a C++11 alternative using lambda expressions and the standard function

template are presented as a modern alternative design.

1. The Decomposition of the Command Dispatcher

2. The Command Class

3. The Command Repository

4. The Command Manager

5. The Command Dispatcher

6. Revisiting Earlier Decisions

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Chapter 5: The Command Line Interface (14 pages)

This chapter marks an important milestone, the creation of the first user executable program.

In addition to building a simple command line interface, we’ll explore how to create an abstract

software interface suitable for both a command line interface and a graphical user interface. Within

the context of the command line interface, we’ll learn techniques for simple parsing and tokenizing

of input text streams.

1. The User Interface Abstraction

2. The Concrete CLI Class

3. Tying It Together: A Working Program

Chapter 6: The Graphical User Interface (24 pages)

In this chapter, we build the Qt-based graphical user interface for the calculator. Here, we’ll

examine different strategies for building GUIs, abstraction of GUI elements, and modularization of

the overall GUI design. Included in the discussion is design for the separation of on-screen widgets

from look-and-feel.

1. Requirements

2. Building GUIs

3. Modularization

4. A Working Program

5. A Microsoft Windows Build Note

Chapter 7: Plugins (38 pages)

In this chapter, I describe how to build a cross-platform plugin system. This system includes the

abstract interface for C++ plugins as well as the operating system specific mechanics involved with

loading plugins and executing plugin functions. In the concrete case of the plugin loader, I explain

the many build tricks that can be used to handle cross-platform code and demonstrate how the

abstract factory pattern provides an elegant design solution to this problem.

1. What Is a Plugin?

2. Problem 1: The Plugin Interface

3. Problem 2: Loading Plugins

4. Problem 3: Retrofitting pdCalc

5. Incorporating Plugins

6. A Concrete Plugin

7. Next Steps

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Chapter 8: New Requirements (24 pages)

Any developer who has ever worked on a production software project quickly learns that new

requirements are always added late in the development cycle. In this chapter, we explore the

addition of new user requests after the original requirements have already been satisfied. The

discussion progresses from fully implemented solutions to design only solutions to vague ideas for

the reader to explore on her own.

1. Fully Designed New Features

2. Designs Toward a More Useful Calculator

3. Some Interesting Extensions for Self-Exploration

Appendix A: Acquiring, Building, and Executing pdCalc (4 pages)

This appendix explains how to download the source code from GitHub and how to build the case

study on Linux and Windows. Once the program is built, readers will want to execute the code

and its included test suite; execution instructions are therefore provided.

1. Getting The Source Code

2. Dependencies

3. Building pdCalc

4. Executing pdCalc

Appendix B: Organization of the Source Code (6 pages)

This appendix simply explains the organization of the source tree for pdCalc. This appendix is

useful for finding the locations for the source files referenced in the text.

1. The src Directory

2. The test Directory

References (2 pages)

This section lists twenty-nine references cited in the book.

Index (3 pages)

This section is a complete index for the book.