13.1 User-defined Data Types

In computer science, user-defined data types allow programmers to create new data types tailored to the specific needs of a program. These types are not built into the programming language but are defined by the programmer. This enhances code readability, organization, and efficiency.

Non-Composite Types

Non-composite data types are fundamental and cannot be broken down into smaller components. They represent single values. Common examples include integers, floating-point numbers, characters, and booleans.

• Integer: Represents whole numbers (e.g., -5, 0, 10).
• Floating-Point Number: Represents numbers with a decimal point (e.g., 3.14, -2.5).
• Character: Represents a single character (e.g., 'a', '7', '$').
• Boolean: Represents a truth value, either true or false.

Defining User-Defined Data Types

User-defined data types are typically defined using keywords provided by the programming language. The specific syntax varies between languages, but the general principle involves specifying the name of the new type and its data type.

Example: Defining a User-Defined Data Type (Conceptual - Language Agnostic)

Consider a scenario where we want to represent a distance. We can define a user-defined data type called Distance which will store a numerical value representing the distance.

Data Type Name	Description	Example
Distance	Represents a physical distance.	e.g., 15.7 meters, 2.5 kilometers
Age	Represents the age of a person.	e.g., 25, 42
Color	Represents a color (e.g., using a string or an integer code).	e.g., "Red", "Blue", 255

Use Cases for User-Defined Data Types

User-defined data types are beneficial in various situations:

• Improved Code Clarity: Using meaningful names for data types makes code easier to understand.
• Data Validation: User-defined types can include validation rules to ensure data integrity.
• Code Reusability: Once defined, a user-defined type can be used throughout a program.
• Abstraction: They hide the internal representation of data, providing a simplified interface.

For instance, in a game development context, you might define a Player data type to encapsulate information like health, position, and score. This makes managing player data much more organized.