chúng ta có thể tái sử dụng một phần dữ liệu mà không cần phải nhớ những gì giá trị thực tế của nó, tất cả chúng ta phải làm là nhớ một tên biến. Trong JavaScript, chúng ta tạo ra một biến bằng cách sử dụng từ khóa var và quy định cụ thể tên chúng tôi | The essence of software design is making decisions about the logical organisation of the software. Sometimes you represent this logical organisation as a model in a defined modelling language such as the UML and sometimes you simply use informal notations and sketches to represent the design. Of course you rarely start from scratch when making decisions about the software organisation but base your design on previous design experience. Some authors think that the best way to encapsulate this design experience is in structured methods where you follow a defined design process and describe your design using different types of model. I have never been a great fan of structured methods as I have always found that they are too constraining. Design is a creative process and I strongly believe that we each tackle such creative processes in individual ways. There is no right or wrong way to design software and neither I nor anyone else can give you a recipe for software design. You learn how to design by looking at examples of existing designs and by discussing your design with others. Rather than represent experience as a design method I prefer a more loosely structured approach. The chapters in this part encapsulate knowledge about software structures that have been successfully used in other systems present some examples and give you some advice on design processes Chapters 11 to 13 are about the abstract structures of software chapter 11 discusses structural perspectives that have been found to be useful when designing software chapter 12 is about structuring software for distributed execution and Chapter 13 is about generic structures for various types of application chapter 13 is a new chapter that I have included in this edition because I have found many students of software engineering have no experience of applications software apart from the interadive systems that they use on an everyday basis on their own computers. Chapters 14 to 16 are concerned with more .
