c# - Design Patterns for User Registration process -

during interview asked create sample application user registration/login following requirements

• should have layered architecture
• use design patterns (at least 2)
• abstract programming
• basic validation

i completed assignment without using design patterns. design pattern have been appropriate user registration?

this question maybe duplicate of this question

in answer have suggested using microsoft membership provider, not possible implement layered architecture?

i hate when 1 forces me use design pattern because should emerge out of design.

anyway, if had use sake of using go repository pattern structuring data access layer , use separated interface design pattern mentioned martin fowler implement that, , stuff in one, go layer supertype pattern , make base class domain layer entities such user, admin, login_info, etc.