V model

V Model:
It is a step by step to  procedure or standard procedure to develop new software. Here all the stages are tested.
In order to overcome the drawback of waterfall and spiral model we use V model.

Verification:
Here we ensure are we building the product right or system right or software right

Validation:
Here we ensure are we building right product or system right or software right.

Drawbacks:

• Initial investment is high
• Documentation is more

Advantages:

• Total time is taken is less(testing is done from early stage).
• All the stages are tested
• Since testing is done in the early stage downward flow of defect will be less.
• Total investment is less(downward flow of defect will be less and const of fixing the defects is less)
• Software quality will be good.
• Requirement changes can be done in any stages.
• Deliverable are parallel

Application

• The requirement is well defined and not ambiguous
• Acceptance criteria are well defined.
• Project is short to medium in size.
• When customers wants quality software which is in short span of time