1.1. What Is Software Construction?

Developing computer software can be a complicated process, and in the last 25 years, researchers have identified numerous distinct activities that go into software development. They include

• Problem definition

• Requirements development

• Construction planning

• Software architecture, or high-level design

• Detailed design

• Coding and debugging

• Unit testing

• Integration testing

• Integration

• System testing

• Corrective maintenance

If you've worked on informal projects, you might think that this list represents a lot of red tape. If you've worked on projects that are too formal, you know that this list represents a lot of red tape! It's hard to strike a balance between too little and too much formality, and that's discussed later in the book.

If you've taught yourself to program or worked mainly on informal projects, you might not have made distinctions among the many activities that go into creating a software product. Mentally, you might have grouped all of these activities together as "programming." If you work on informal projects, the main activity you think of when you think about creating software is probably the activity the researchers refer to as "construction."

This intuitive notion of "construction" is fairly accurate, but it suffers from a lack of perspective. Putting construction in its context with other activities helps keep the focus on the right tasks during construction and appropriately emphasizes important nonconstruction activities. Figure 1-1 illustrates construction's place related to other software-development activities.

Figure 1-1. Construction activities are shown inside the gray circle. Construction focuses on coding and debugging but also includes detailed design, unit testing, integration testing, and other activities

As the figure indicates, construction is mostly coding and debugging but also involves detailed design, construction planning, unit testing, integration, integration testing, and other activities. If this were a book about all aspects of software development, it would feature nicely balanced discussions of all activities in the development process. Because this is a handbook of construction techniques, however, it places a lopsided emphasis on construction and only touches on related topics. If this book were a dog, it would nuzzle up to construction, wag its tail at design and testing, and bark at the other development activities.

Construction is also sometimes known as "coding" or "programming." "Coding" isn't really the best word because it implies the mechanical translation of a preexisting design into a computer language; construction is not at all mechanical and involves substantial creativity and judgment. Throughout the book, I use "programming" interchangeably with "construction."

In contrast to Figure 1-1's flat-earth view of software development, Figure 1-2 shows the round-earth perspective of this book.

Figure 1-2. This book focuses on coding and debugging, detailed design, construction planning, unit testing, integration, integration testing, and other activities in roughly these proportions

Figure 1-1 and Figure 1-2 are high-level views of construction activities, but what about the details? Here are some of the specific tasks involved in construction:

• Verifying that the groundwork has been laid so that construction can proceed successfully

• Determining how your code will be tested

• Designing and writing classes and routines

• Creating and naming variables and named constants

• Selecting control structures and organizing blocks of statements

• Unit testing, integration testing, and debugging your own code

• Reviewing other team members' low-level designs and code and having them review yours

• Polishing code by carefully formatting and commenting it

• Integrating software components that were created separately

• Tuning code to make it faster and use fewer resources

For an even fuller list of construction activities, look through the chapter titles in the table of contents.

With so many activities at work in construction, you might say, "OK, Jack, what activities are not part of construction?" That's a fair question. Important nonconstruction activities include management, requirements development, software architecture, user-interface design, system testing, and maintenance. Each of these activities affects the ultimate success of a project as much as construction at least the success of any project that calls for more than one or two people and lasts longer than a few weeks. You can find good books on each activity; many are listed in the "Additional Resources" sections throughout the book and in Chapter 35, "Where to Find More Information," at the end of the book.