ProtoType Model.

Prototype Model:
It is a step by step procedure or standard procedure to develop the software.

Advantages:

• Customer will get to know how the software looks in the early stage itself.
• There will be improved communication between customers and developers.
• Requirement changes are allowed.
• Missing functionalities can be easily figured out.
• Errors can be detected much earlier thereby saving a lot of effort and cost, besides enhancing the quality of the software.
• The developed prototype can be reused by the developer for more complicated projects in the future.

Drawback: 

• Total time taken is high.
• Total investment is more
• There will be delay in releasing the software to customer.
• Poor Documentation due to continuously changing customer requirements.

Applications:

• If the customer is new to the software and developers are new to the domain.
• When the customer is not clear about requirements.