Requirements Gathering With OOA&D

Let the customer talk--find what the system needs to Do...(later can think how the system will do)
U need to imagin and relised how the system actually work to get better requirements..
Ask the questions to identify actually what they need..,.........
want to imagin by listing the steps for each tasks one by one.......

1. List out the steps for a task(for one task may be 7 steps to complete the task)
2. Write down the ALTERNATE PATHS for each steps which may be affect for that task
3.

Use cases
Use case is what the system does to accomplish agoal...
List of steps that the system has to do work correctly...
usecase is for specially accomplishing one perticular goal...
For each goal required seperate use cases..

We can easily realise soround stuffs of task by creating use cases(Ex-door want to close automatically)...therwise never can it properly..
We can use use cases for explain the system to customer or Boss...
want to maintain as simple with everyday language..


Use cases
1. Every use case must have a clear value to the system(mean usecase help to the achive the goals)
2. Every use case must have definite starting and ending point..
3. Every use case have a external initiator...it may be out side the system.


Ex-
1. clear value - Todd at the bed, dog out side the .....no warries...
2. External Initiator-dog barks for to be let out
3. stoping point -The door shut automatically

AFTER WANT TO CHECK REQUIREMENT LIST AND USE CASES TO CHECK WHETHER ALL THE REQUIRMENTS HAS COVERED OR NOR...
Compare the requirements to apply foe each use case steps....

With Requiremnts and Use cases and after comparing and finalising it , can start the coding.................

First implement main uce cases and second vertion do for the alternate paths...

Also checking on use cases we can identify correct requirements..............

Make sure ur requirements cover all the steps in the use cases for ur system..

Use use cases to find out about things ur customer forget to tell u......

Use cases will reveal any incomplete or missing requirements that might have to add to ur system....

page 139 hv definitions in a box...............

use cases hv two paths....
1. main path(this is the process hapening most of the time)
2. Alternate paths(some time may be happen)

Senario is a complete path through a use case , from the first step to the last.

Any time u change the use case , want to recheck the requirement list against to the new use cases..
Most use cases hv several different senarios..
But thye always share the same user goal..