Notes on Software Design Approaches

Introduction

• Welcome to Gate Smashers!
• Lecture Topic: Various approaches for software design.

Software Design Overview

• Occurs after completion of:
  • Requirement analysis
  • Risk analysis
  • Software project management
• Important to design before coding/implementation.
• Analogy: Building construction requires architectural design before starting.

Design Approaches

1. Functional-Oriented Design

• Focus on functions related to the system.
• Divide the system into smaller subsystems/modules (top-down approach).
• Key aspects:
  • Divided & conquer approach.
  • Final system created by merging completed functional modules.
• Example systems:
  • ATM
  • Library Management System (LMS)
  • Functions include:
    • Issue book
    • Return book
• Uses Data Flow Diagrams (DFD) for graphical representation.

2. Object-Oriented Design

• Focus on objects and their interactions.
• Define classes consisting of objects (bottom-up approach).
• Key aspects:
  • Each object belongs to a class with members (data and functions).
  • Identify classes such as student, faculty, and book.
• Example for LMS:
  • Student Class: ID, name.
  • Faculty Class: ID, name.
  • Book Class: ID, name, availability.
• Uses Unified Modeling Language (UML) for graphical representation.

Comparison of Approaches

• Functional-oriented design is older and mature.
• Object-oriented design is newer with evolving concepts.
• Both approaches are not mutually exclusive and can coexist in practice.

Next Lecture

• Topics to cover:
  • What are DFDs?
  • How to design DFDs?
  • Levels of DFDs.
  • Introduction to UML.

Conclusion

• Thank you for attending!