UML Class Diagram

A UML Class diagram is a visual representation of the classes and their relations in an object oriented program.

Classes are represented as a combination of:

• Their name
• Attributes
• Methods

Example

 class Door {
   - is_closed: bool
   + toggle_is_closed(): void
   - changeLockMechanism(): void
 }

A Door Class.

Note the presence of it’s name, attribues and methods.

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Visibility

An attribute or method may be given a prefix to denote it’s visibility to the outside world:

• public → +
• private → -
• protected → #
• package → ~