Saturday, August 5, 2017

Designing Traditional Components

Designing Traditional Components

  • Introduction : Traditional components are designed based on different constructs like 
    • Sequence,
    • Condition, 
    • Repetition. 
  • Sequence implements processing steps that are essential in the specification of any algorithm. 
  • Condition provides the facility for selected processing based on some logical occurrence. 
  • Repetition allows for looping. 
  • These three constructs are fundamental to structured programming— an important component-level design technique.
  • The use of the structured constructs reduces program complexity and thereby enhances readability, testability, and maintainability. 
  • The use of a limited number of logical constructs also contributes to a human understanding process that psychologists call chunking.
  • Graphical Design Notation 
    • A picture is worth a thousand words,” but it’s rather important to know which picture and which 1000 words. 
    • There is no question that graphical tools, such as the UML activity diagram or the flowchart, provide useful pictorial patterns that readily depict procedural detail. 
    • The activity diagram allows you to represent sequence, condition, and repetition— all elements of structured programming. 
    • It is a descendent of an earlier pictorial design representation (still used widely) called a flowchart. 
    • A flowchart, like an activity diagram, is quite simple pictorially. A box is used to indicate a processing step. A diamond represents a logical condition, and arrows show the flow of control
Graphical Design Notation

  • Tabular Design Notation 
    • In many software applications, a module may be required to evaluate a complex combination of conditions and select appropriate actions based on these conditions.
    • Decision tables provide a notation that translates actions and conditions into a tabular form. 
    • The table is difficult to misinterpret and may even be used as a machine-readable input to a table-driven algorithm.
Decision tables | Tabular Design Notation

  • Program Design Language 
    • Program design language (PDL), also called structured English or pseudocode, 
    • It incorporates the logical structure of a programming language with the free-form expressive ability of a natural language (e.g., English). 
    • Narrative text (e.g., English) is embedded within a programming language-like syntax. 
    • Automated tools can be used to enhance the application of PDL.
    • A basic PDL syntax should include constructs for 
      • Component definition, 
      • Interface description, 
      • Data declaration, 
      • Block structuring, 
      • Condition constructs, 
      • Repetition constructs, 
      • Input-output (I/O) constructs. 
    • It should be noted that PDL can be extended to include keywords.

Program design language (PDL)

1 comment:

  1. Traditional components within the designing which is really informative to know about. Thank you so much. Kovai IT software solutions | Best IT company in coimbatore