Class Diagram

classDiagram
    direction LR
    class Animal {
      +String name
      +int age
      +makeSound() void
    }
    class Dog {
      +String breed
      +fetch() void
    }
    class Cat {
      +bool indoor
      +purr() void
    }
    class Trainer {
      +train(Animal a) bool
    }
    Animal <|-- Dog
    Animal <|-- Cat
    Trainer "1" o-- "*" Animal : trains