Requirements ( Functional , non-functional and user requirements)

can you please provide examples on requirements of the type ( functional , non-functional and user requir开发者_如何学编程ements ) of a website social network ( lets say the facebook ) ?

thanx in advance

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Here are some examples for what requirements should be like for Facebook. However it's worth a warning: there isn't a single, agreed definition for what each type of requirement is, so I've given a definition for you I've chosen for each case.

I'm sure all of these can be improved in one way or another, but I feel these are decent requirements.

User Requirements

High level requirements that describe what a user can achieve. These are the needs that the system fulfil, similar to business requirements

• U1. Users can post a textual update of their current mood or status.
• U2. Users can choose whether the post described in U1 is shared with Friends, Everyone, or Nobody other than themselves.
• U3. Users are presented with a list of posts made by people they are friends with or posts that are made to Everyone (see U2).
• U4. The posts that appear in the lists U3 are filtered to only contain those that the user will find relevant or interesting
• U5. The posts that appear in the lists U3 are ordered so that those the user will find highly relevant, and have not been seen previously by the user are towards the top of the list.

Function Requirements

Functional requirements provide highly specific details that allow designers, developers and testers to create a system to meets precise specifications. I've mapped them to user requirements from above

• F1. Posts can be 63,206 characters long. [ref U1]
• F2. Posts can be contain unicode characters. [ref U1]
• F3. Posts may not contain any any of the following formatting, other than what can be provided by unicode characters - bold, strikethrough, underline [ref U1]
• F4. 80% or more of posts in a users' post list (U3) should be from their friends. The remaining posts can be public posts or sponsored posts.

Non Functional Requirements

qualities and characteristics of the system that are not features. Again can be mapped to user or functional requirements

• N1. After submitting a post through the web interface (see U1), it will be available to appear to in other users' lists of posts (see U3) within 30 seconds for 90% of posts.
• N2. An update to a users list of posts (either the initial view of a list, or an extension to the list when scrolling to the bottom) appears in 3 seconds for 90% of users.
• N3. 50% of users can post a status update within 1 minute of starting to try and post without having used the application before or receiving help.