1	Introduction to C# Andrew Scott Computing Department Lancaster University, UK
2	C# Keywords
3	Last week… creating exceptions
4	Overloading Method Names
5	Namespaces
6	Namespaces and Using
7	Namespaces and Using
8	Interfaces Abstract definition of an object ‘characteristic’ Includes abstract definition of Indexers Methods Properties Names should start with an I IComparable
9	Classes and Interfaces Classes implement one or more Interfaces Multiple inheritance Classes can extend only one base class Single inheritance
10	Interfaces v Classes Interface General characteristic: Printable Abstract Class Limited grouping: Processor Class Specific implementation: Intel Pentium III
11	Polymorphism
12	Polymorphism
13	…and for classes
14	…and for classes
15	Preventing Inheritance sealed Prevents classes inheriting from a class
16	Collections Implement IEnumerable IEnumerator GetEnumerator() For example, System.Array class Iterator: foreach(type var in ICollection)
17	Collection Classes
18	Collection Classes
19	Arrays
20	Structs No inheritance Passed by value Class based objects passed by reference Value type and always they have value Cannot be null, unlike class based objects Can have methods and properties Cannot have a finalize method
21	Enumerators
22	Enumerators
23	Access Rights Public: Not restricted Protected: Containing class or types derived from it Internal: Current project/assembly Protected internal: Current project/assembly Containing class or types derived from it Private: Containing type
24	Access to Members of Types Class [private, by default] Public, protected, internal, protected internal, private Enum [public] Interface [public] Struct [private] Public, internal, private
25	C# Keywords