What’s a Use Case?

1. Is a detailed Description of the user interaction with the system
2. Identifies the system, and it’s user(s). 
1. sytem is gmail.
2. user -compose email, person who wants to send email, check etc is user
3. Illustrates interaction between user and system. 
1. What happens when user does action.. say check email etc and what is sytem reaction
4. Defines the system’s response/behavior.

DIID