Lecture 13: Functional Requirements

Unit 3: Requirement Analysis and Design (4353202)

Lecture Agenda

• Recap of SRS
• What are Functional Requirements?
• Examples of Functional Requirements
• How to Write Good Functional Requirements
• Functional vs. Non-Functional Requirements
• Key Takeaways

Recap of SRS

The Software Requirement Specification (SRS) is a document that describes the intended purpose, functionality, and behavior of a software system. It serves as a contract between the client and the developers.

What are Functional Requirements?

Functional requirements define what a system is supposed to do. They describe the behavior and functions of the system and its components.

They are the features that a user will directly interact with.

Examples of Functional Requirements

For an Online Shopping System:

• The user shall be able to search for products.
• The system shall provide a shopping cart for users to add products to.
• The user shall be able to log in to their account using their email and password.
• The system shall send an order confirmation email to the user after a successful purchase.
• The system shall allow administrators to add, edit, and delete products.

How to Write Good Functional Requirements

• Be Specific and Clear: Avoid ambiguous language.
• Be Testable: It should be possible to verify that the requirement has been met.
• Be Atomic: Each requirement should describe a single function.
• Use "Shall" Statements: Use a consistent format, such as "The system shall...".
• Include User Roles: Specify which users can perform the function.

Functional vs. Non-Functional Requirements

Key Takeaways

• **Functional requirements** define the specific behaviors and functions of a system.
• They are the **"what"** of the system.
• They should be **specific, testable, and atomic**.
• They are distinct from non-functional requirements, which define the **qualities** of the system.

Next Lecture

Topic: Non-Functional Requirements

Q & A

Questions & Discussion