2.1 Create Types

2.1 Create Types

1. 3 categories

   • Value Type
     • Contain value directly
     • Criteria -
     • Inheritance
       • Must use STRUCTS (cannot Inherit directly)
         • STRUCT eg => public struct Point { definition of Struct}
   • Reference Type
     • Reference specific value (e.g. URL)
   • Pointer Type
   • Generics R Good (unlike medication)

2. Extensions and Overrides

   • Extensions
     • Called like a regular method
     • e.g. Method (this ExtMethod methodname)
     • BEst use case - LINQ
   • Overrides
   • If sealed = no extension/override

3. Classes

   • Functions vs Methods
     • Functions - RETURN VALUE
     • Methods - Just do work. C# Preferred
     • Preferred - Split into Smaller Methods
   • SOLID Design Principles
     • S = Single Responsibility
       • Class should only be responsible for ONE THING
     • O = Open/Closed
       • Open for Extension, but Closed for Modification
     • L = Liskov Substitution
     • I =Interface Segregation
     • D = Dependency Inversion

4. Generics

   • Parameter = Type (NOT SPECIFIC
   • Allows Nullables (usaally a coding nightmare - value types e.g. bool)
   • Constraints
     • Where T : Struct
       • Only Nullable nots allowed
     • Where T : Class
       • REFERENCE ONLY
     • where T : new
       • Must have default constructor
     • Where T : <base class> (i.e. T: <string>
       • T must be a string or derive from a string
     • Where T : <interface>
       • T must be interface or implement it