Category: C#

Define lightweight value types with struct.

Name discrete values with enum types.

Model immutable data with record / record struct.

Write reusable type-safe code with generics.

Build Repository / Box style reusable types.

Parameterize methods independently of their declaring type.

Define incomplete base types with abstract members.

Define contracts with interfaces; implement multiple interfaces on a class.

Prevent inheritance with sealed classes or seal overrides.

Use single inheritance hierarchies and interface-based composition.