Objectives: Introduction Over View of System Analysis and Design
Software Design and Documentation Tools
Download 0.94 Mb. View original pdf
|
- Navigate this page:
- 8.5.1.1 Basic Elements
- 8.5.1.2 Decision
- 8.5.1.3 Iteration
| 8.5 Software Design and Documentation Tools Well – designed, modular software is more likely to meet the maintenance, reliability, and testing requirements. Three specific tools are discussed Structured flowcharts, HIPO diagrams, and Warnier / Orr diagrams. 8.5.1 Structured Flowcharts Structured flowcharts, also called Nassi-Schneiderman Charts, are graphic tools that force the designer to structure software that is both modular and top- down. They provide a structure that can be retained by programmers who develop the application software. Organization responsibilities vary. In some organizations, analysts are responsible for developing module logic, while in others that responsibility is delegated to the programmer. In either case, the programmer should be well versed in the use of structured flowcharts. 8.5.1.1 Basic Elements There are three basic elements used in developing structured flowcharts process, decision, and iteration. (There are many similarities between these elements and the components used in structured English) Process A rectangular box, the process symbol, represents Simple processes or steps in a program. This symbol represents initialization of values, input and output activities, and calls to execute other procedures. A name of brief description written in the box states the purpose of the process. The succession of steps is shown using several process boxes. 8.5.1.2 Decision The decision symbol represents alternative conditions that can occur and that the program must have a manner of handling. They show the equivalent of the IF-THEN- ELSE structures common in many programming languages. As examples will show, the decision symbol may show actions for more than two alternatives at the same time. 8.5.1.3 Iteration The iteration symbol represents looping and repetition of operations while a certain condition exists or until a condition exists. The form of the iteration symbol clearly shows the scope of the iteration, including all processes and decisions that are contained within the loop. The left – hand portion of the symbol shows the path of repetition to follow until the conditions controlling the iteration are satisfied. Download 0.94 Mb. Share with your friends:
|