Beginning Software Engineering

Rod Stephens

• Éditeur: Wrox
• Année: 2015
• ISBN:
  9781118969175
• Édition: 1
• Sujet: Informatik
• Sous-sujet: Softwareentwicklung

A complete introduction to building robust and reliable software Beginning Software Engineering demystifies the software engineering methodologies and techniques that professional developers use to design and build robust, efficient, and consistently reliable software. Free of jargon and assuming no previous programming, development, or management experience, this accessible guide explains important concepts and techniques that can be applied to any programming language. Each chapter ends with exercises that let you test your understanding and help you elaborate on the chapter's main concepts. Everything you need to understand waterfall, Sashimi, agile, RAD, Scrum, Kanban, Extreme Programming, and many other development models is inside!

• Describes in plain English what software engineering is
• Explains the roles and responsibilities of team members working on a software engineering project
• Outlines key phases that any software engineering effort must handle to produce applications that are powerful and dependable
• Details the most popular software development methodologies and explains the different ways they handle critical development tasks
• Incorporates exercises that expand upon each chapter's main ideas
• Includes an extensive glossary of software engineering terms

PART I
Software Engineering Step-by-Step

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• CHAPTER 1: Software Engineering from 20,000 Feet
• CHAPTER 2: Before the Beginning
• CHAPTER 3: Project Management
• CHAPTER 4: Requirement Gathering
• CHAPTER 5: High-Level Design
• CHAPTER 6: Low-Level Design
• CHAPTER 7: Development
• CHAPTER 8: Testing
• CHAPTER 9: Deployment
• CHAPTER 10: Metrics
• CHAPTER 11: Maintenance

Software and cathedrals are much the same. First we build them, then we pray.

—SAMUEL REDWINE

In principle, software engineering is a simple two-step process: (1) Write a best-selling program, and then (2) buy expensive toys with the profits. Unfortunately, the first step can be rather difficult. Saying “write a best-selling program” is a bit like telling an author, “Write a best-selling book,” or telling a baseball player “triple to left.” It’s a great idea, but knowing the goal doesn’t actually help you achieve it.

To produce great software, you need to handle a huge number of complicated tasks, any one of which can fail and sink the entire project. Over the years people have developed a multitude of methodologies and techniques to help keep software projects on track. Some of these, such as the waterfall and V-model approaches, use detailed requirement specifications to exactly define the wanted results before development begins. Others, such as Scrum and agile techniques, rely on fast-paced incremental development with frequent feedback to keep a project on track. (Still others techniques, such as cowboy coding and extreme programming, sound more like action adventure films than software development techniques.)

Different development methodologies use different approaches, but they all perform roughly the same tasks. They all determine what the software should do and how it should do it. They generate the software, remove bugs from the code (some of the bugs, at least), make sure the software does more or less what it should, and deploy the finished result.

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NOTE I call these basic items “tasks” and not “stages” or “steps” because different software engineering approaches tackle them in different ways and at different times. Calling them “stages” or “steps” would probably be misleading because it would imply that all projects move through the stages in the same predictable order.

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The chapters in the first part of this book describe those basic tasks that any successful software project must handle in some way. They explain the main steps in software development and describe some of the myriad ways a project can fail to handle those tasks. (The second part of the book explains how different approaches such as waterfall and agile handle those tasks.)

The first chapter in this part of the book provides an overview of software development from a high level. The subsequent chapters explain the pieces of the development process in greater detail.

CHAPTER 1
Software Engineering from 20,000 Feet

There are two ways of constructing a software design. One way is to make it so simple that there are obviously no deficiencies. The other way is to make it so complicated that there are no obvious deficiencies. The first method is far more difficult.

—C.A.R. HOARE

WHAT YOU WILL LEARN IN THIS CHAPTER:

• The basic steps required for successful software engineering
• Ways in which software engineering differs from other kinds of engineering
• How fixing one bug can lead to others
• Why it is important to detect mistakes as early as possible

In many ways, software engineering is a lot like other kinds of engineering. Whether you’re building a bridge, an airplane, a nuclear power plant, or a new and improved version of Sudoku, you need to accomplish certain tasks. For example, you need to make a plan, follow that plan, heroically overcome unexpected obstacles, and hire a great band to play at the ribbon-cutting ceremony.

The following sections describe the steps you need to take to keep a software engineering project on track. These are more or less the same for any large project although there are some important differences. Later chapters in this book provide a lot more detail about these tasks.

REQUIREMENTS GATHERING

No big project can succeed without a plan. Sometimes a project doesn’t follow the plan closely, but every big project must have a plan. The plan tells project members what they should be doing, when and how long they should be doing it, and most important what the project’s goals are. They give the project direction.

One of the first steps in a software project is figuring out the requirements. You need to find out what the customers want and what the customers need. Depending on how well defined the user’s needs are, this can be time-consuming.

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WHO’S THE CUSTOMER?

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Sometimes, it’s easy to tell who the customer is. If you’re writing software for another part of your own company, it may be obvious who the customers are. In that case, you can sit down with them and talk about what the software should do.

In other cases, you may have only a vague notion of who will use the finished software. For example, if you’re creating a new online card game, it may be hard to identify the customers until after you start marketing the game.

Sometimes, you may even be the customer. I write software for myself all the time. This has a lot of advantages. For example, I know exactly what I want and I know more or less how hard it will be to provide different features. (Unfortunately, I also sometimes have a hard time saying “no” to myself, so projects can drag on for a lot longer than they should.)

In any project, you should try to identify your customers and interact with them as much as possible so that you can design the most useful application possible.

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After you determine the customers’ wants and needs (which are not always the same), you can turn them into requirements documents. Those documents tell the customers what they will be getting, and they tell the project members what they will be building.

Throughout the project, both customers and team members can refer to the requirements to see if the project is heading in the right direction. If someone suggests that the project should include a video tutorial, you can see if that was included in the requirements. If this is a new feature, you might allow that change if it would be useful and wouldn’t mess up th...