This book describes how to design software using either a structured or object-oriented design paradigm. It assumes the reader already knows how to write software code, using either Java or Python, and uses this assumption to review program design criteria. This book then transitions the reader to thinking more abstractly about software design, introducing concepts and design models when appropriate.

Software design is a broad and complex topic, with many opinions on what it means to design software. This book addresses these challenges by first discussing software design as a detailed representation of the internal structures and behaviors of the code. It uses a case study to illustrate design thinking, including the use of abstraction, information hiding, coupling, cohesion, simplicity, performance, and security. Once the core elements of software design have been presented, five software design topics are covered. These five topics are: user interface design, quality assurance, secure design, design patterns, and persistent data storage design. These five topics are presented in a way that allows the learner to cover these topics in whatever order they deem relevant to their situation.

This book presents a holistic description of software design. It takes the reader from something the author assumes they know – programming – to having a solid understanding of the key elements of software design. This book covers software design topics relevant to today’s developers while illustrating ways to apply these topics by way of a case study.

The bottom-up learning approach used in this book is based on findings from learning research which strongly suggests that people learn best when able to use their pre-existing knowledge to make connections to new information/knowledge. While many readers may find Part I (Program Design Fundamentals) a review of their existing knowledge, this material is important as a means to transition the reader to the more abstract notions associated with software design. This portion of the book is covered in about two weeks of a 15-week semester.