Data Representation Chapter 13

Data Representation Overview

• Explores user-defined data types and their importance in programming.
• Covers both non-composite and composite data types and their usage.
• Discusses the design of appropriate user-defined data types for specific problems.

File Organisation and Access Methods

• Different methods of file organisation:
  • Serial
  • Sequential
  • Random
• File access methods:
  • Sequential access
  • Direct access

Key Concepts in Data Types

• User-defined data types are tailored to match program requirements, based on primitive types or previously defined types.
• Non-composite data types do not reference other data types and can be primitive or user-defined.

Non-composite Data Types

• Examples include primitive types and user-defined types.
• Frequently used for special purposes.
• Enumerated data types (specific list of items with an implied order) facilitate the creation of ordered sets.

Practical Exercises

• Selecting appropriate data types for various scenarios:
  • Name (string)
  • Student's mark (numeric)
  • Recorded temperature (float)
  • Start date for a job (date)
  • Item sold status (boolean)
• Creating pseudocode for a record structure storing animal data:
  • Attributes to include: Name, Species, Date of Birth, Location, Birth status, Notes.

Advanced Concepts

• Introduction to hashing algorithms for data retrieval and storage.
• Understanding binary floating-point real numbers:
  • Techniques for converting between binary and denary representations.
  • Normalisation of binary floating-point numbers.
• Awareness of underflow and overflow occurrences in binary representation.
• Insights into how binary representation can result in rounding errors.