UML Diagrams

The blueprints of software.

UML Diagrams

Analogy: concept

UML (Unified Modeling Language) is like Architectural Blueprints:

Before building a skyscraper, you draw plans.

Class Diagram: The floor plan (Structure).
Sequence Diagram: The script of a play (Interactions).
Use Case Diagram: The menu of services (Functionality).

The Blueprint Maker

Explore the three most common types of UML diagrams.

UML Blueprint Maker

Car

- speed: int
- color: String

+ drive(): void
+ stop(): void

Engine

- horsepower: int

+ start(): void

Shows Structure

Key Concepts

Class Diagram: Shows classes, attributes, methods, and relationships.
- Static view of the system.
- Uses boxes and arrows.
Sequence Diagram: Shows how objects interact over time.
- Dynamic view.
- Uses lifelines (vertical lines) and messages (horizontal arrows).
Use Case Diagram: Shows what the system does for the user (Actors).
- Functional view.
- Uses stick figures and ovals.

Why use UML?

Communication: A picture is worth 1000 lines of code.
Planning: Catch design flaws before coding.
Documentation: Help new developers understand the system.

Up Next