The Software Development Process

Documentation (analysis stage)

• The systems analyst must document the clients needs by drafting formal reports:
• requirements specification
• system specification

Design Representations

• There are a number of commonly used forms of design representation in common use.
• Examples include:
• structure diagrams
• pseudocode

Structure Diagram

• A commonly used syntax for structure diagrams is as follows:

• A procedure

• A loop

• A decision

• A single task

An example:

• A structure diagram allows the design of a program to be drawn out in diagrammatic form. Here is an example:

Pseudocode

• Pseudocode is another example of a method of describing a program.
• Simple English words are used to describe the steps of the algorithm and any refinements made.

Pseudocode - Example

• 1. Display information
• 2. Get details
• 3. Do calculation
• 4. Display answer
• Refine step 2
• 2.1 display prompt
• 2.2 get value
• 2.3 while value out of range
• 2.4 display error message
• 2.5 get value
• 2.6 loop

• Top level design

• Notice the numbering system

• Simple English
• words in a familiar
• program form

Designing the Solution

• Once the needs of the user are clearly understood and documented, software development can move onto the next stage, involving the DESIGN of the system.
• Design of the User Interface
• Design of the structure of the software
• Design of the detailed logic of the software

Implementation

• The next stage involves turning the carefully structured design into a working solution.

Choosing an Environment

• Before we can implement a solution we must decide on the programming environment which is most suitable.
• Languages are generally designed for a specific purpose.