Worksheet: J8

Worksheets are self-guided activities that reinforce lectures. They are not graded for accuracy, only for completion. They are due, on github by 11:59pm on the day of the lecture.

Create a new repo using all the steps in Lab 0 called yourgitusername-worksheet-J8. Submit a file called worksheet-J8.md in your repo for this assignment.

Questions

1. What is the difference between a functional and non-functional requirement?

   Reveal Solution

   Both must be testable and capture behavior of the system, but a non-functional requirement is usually some kind of “-ity” (usability, compatibility, security, speed, performance, etc.) that isn’t generally something that a single developer could code up (like, for example, a widget on a GUI).

2. Give two example functional requirements for Instagram.com.

   Reveal Solution

   Many options here;

   • The system shall allow the user to upload a photo to their account.
   • The system shall allow the user to ‘like’ photos of users they are following

3. Give two example non-functional requirements for Instagram.com.

   Reveal Solution

   Many options here;

   • The system shall encrypt all passwords stored in the database
   • The system shall load each image within one second

4. Draw a use case diagram for Instagram.com with at least three uses cases shown, where at least one use case extends another, and there are two actors.

   Reveal Solution

   Answers given in class.

5. Why has software engineering evolved to often embrace agile development models over waterfall ones?

   Reveal Solution

   It is generally impossible to obtain clear, consistent, and complete requirements up-front at the start of a software project, as the waterfall model assumes. Therefore, agile approaches can be used to have flexibility around the requirements discovery that inevitably happens during the software development process.

6. Draw a diagram where there are at least two interconnected paths: a critical path, and at least one non-critical path.

   Reveal Solution

   Answers given in class.