What is a use case diagram and when to use it?

Question

Accepted Answer

**Use Case Diagram** — UML diagram showing system functionality from user perspective. **When to use:** - During requirements gathering. - To communicate with non-technical stakeholders. - To define system boundaries. - To identify actors and their interactions. **Components:** ``` Actors: People or systems interacting with the system Use Cases: Functions or services provided Associations: Links between actors and use cases Include: Mandatory sub-behavior (<>) Extend: Optional behavior (<>) ``` **Example:** ``` Actor: Customer Use Cases: Browse Catalog, Place Order, Make Payment Include: Place Order <> Verify Stock Extend: Place Order <> Apply Discount ``` **Benefits:** Simple, visual, stakeholder-friendly.

Systems Analyst: What is a use case diagram and when to use it?