Sams Teach Yourself C++ in 21 Days

Analysis activity diagrams Activity diagrams describing interactions among

objects in the problem domain

Systems analysis Report and diagrams describing low-level and hard-

ware systems on which the project will be built

Application analysis document Report and diagrams describing the customer’s

requirements specific to this particular project

Operational constraints report Report describing performance characteristics and

constraints imposed by this client

Cost and planning document Report with charts and graphs indicating projected

scheduling, milestones, and costs

Step 3: The Design Phase ....................................................................................

Analysis focuses on understanding the problem domain, whereas the next step of the

processes, design, focuses on creating the solution. Designis the process of transforming

your understanding of the requirements into a model that can be implemented in soft-

ware. The result of this process is the production of a design document.

A design document can be divided into two sections: Class Design and Architectural

Mechanisms. The Class Design section, in turn, is divided into static design (which

details the various classes and their relationships and characteristics) and dynamic design

(which details how the classes interact).

The Architectural Mechanisms section of the design document provides details about

how you will implement object persistence, concurrency, a distributed object system, and

so forth. The rest of today’s lesson focuses on the class design aspect of the design docu-

ment; other lessons in the rest of this book explain elements of how to implement various

architectural mechanisms.

What Are the Classes?....................................................................................

As a C++ programmer, you are now used to creating classes. Formal design methods

require you to separate the concept of the C++ class from the concept of the design class,

although they are intimately related. The C++ class you write in code is the implementa-

tion of the class you designed. There is a one-to-one relationship: Each class in your

design corresponds to a class in your code, but don’t confuse one for the other. It is cer-

tainly possible to implement your design classes in another language, and the syntaxof

the class definitions might be changed.

350 Day 11

TABLE11.1 continued

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