Class Diagram

Class diagrams show the structure of a system using classes, attributes, methods, and relationships.

Basic Class

classDiagram
  class Animal {
    +String name
    +int age
    +eat() void
    -sleep()
  }

Relationships

Inheritance

classDiagram
  Animal <|-- Dog
  Animal <|-- Cat

Composition & Aggregation

classDiagram
  Car *-- Engine
  Library o-- Book

Association & Dependency

classDiagram
  Teacher --> Student
  Client ..> Service

Annotations

classDiagram
  class Shape
  <<Interface>> Shape
  class Circle
  Shape <|-- Circle

Generic Types

classDiagram
  class List~T~ {
    +add(item T)
    +get(index int) T
    +size() int
  }

Full Example

classDiagram
  class Vehicle {
    +String make
    +String model
    +start() void
    +stop() void
  }
  class Car {
    +int doors
    +drive() void
  }
  class Truck {
    +int payload
    +haul() void
  }
  class Engine {
    +int horsepower
    +rev() void
  }

  Vehicle <|-- Car
  Vehicle <|-- Truck
  Vehicle *-- Engine