How do I decide whether to use a struct or a class for my game’s data model in C++?

Struct vs Class: Choosing the Right Data Model in C++

Fundamentals of Structs and Classes

In C++, both struct and class can have public, protected, and private members, can utilize inheritance, and can contain member functions. However, they serve different purposes in practice.

When to Use Structs

• Plain Old Data (POD): Use structs when you need simple data structures that do not require complex behaviors or functions. They are ideal for storing related data without any additional functionality.
• Memory Layout: Since structs are often used for POD, their memory layout is more predictable, making them suitable for game development scenarios where memory alignment and performance are crucial.
• No Memory Management: Generally, avoid using pointers with structs. They should be self-contained without dynamic memory management to ensure simplicity and efficiency.

When to Use Classes

• Encapsulation and Abstraction: Classes are preferred when you need to encapsulate data with behavior. They allow you to hide internal states and provide public interfaces for manipulation.
• Inheritance: Use classes if you require inheritance, polymorphism, or virtual functions. This facilitates code reuse and the design of complex object behaviors.
• Data with Behavior: Classes are suitable for objects that operate on their data, such as game entities or complex game logic components.

Considerations for Game Data Models

In game development, especially with C++, the choice between structs and classes can significantly impact performance:

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• Performance: Structs, due to their simplicity and straightforward memory layout, might be more performant in tight loops and frequently updated structures, such as physics calculations
• Maintaining Code: While classes provide more features like constructors and destructors, they require careful management. Use classes for entities where encapsulation is beneficial, such as player characters or AI systems.