Mermaid Class Diagrams

Class diagrams model object-oriented structures.

They can show:

classes
attributes
methods
inheritance
composition
aggregation
association
dependency

Basic Class Syntax

classDiagram
    class User {
        -String username
        -String password
        +login() boolean
        +updateProfile() void
    }

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Visibility

Common visibility symbols:

Symbol	Meaning
`+`	Public
`-`	Private
`#`	Protected

Relationships

Common relationships include:

Syntax	Meaning
`<	--`
`*--`	Composition
`o--`	Aggregation
`-->`	Association
`..>`	Dependency
`..	>`
`--`	Solid link
`..`	Dashed link

Relationship Example

classDiagram
    Animal <|-- Dog
    Animal <|-- Cat
    Car *-- Engine
    Library o-- Book

    class Animal {
        +int age
        +makeSound()
    }

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Small Library Example

classDiagram
    class Library {
        +String name
    }

    class Book {
        +String title
    }

    Library "1" o-- "*" Book : contains

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