2. History  We first begin with Java which was released in 1995 by Sun Microsystems  Initially Java was 100% interpreted at runtime and was very slow  Eventually Just-in-Time compilers were created and used  The increased performance of Java and portability helped it grow in popularity

3. History  The theory that Java applications could be developed on Windows and then easily be deployed on Unix platforms was clearly a threat to Microsoft  So Microsoft created their own Java Virtual Machine which was fairly reliable  However, their JVM introduced incompatible extensions which ruined portability

4. History  So Sun sued Microsoft for violating the licensing terms  This hindered Microsoft’s JVM making it obsolete quickly as Sun updated their JVM  Clearly Microsoft and Java did not mix well

5. History  In 1999 Anders Hejlsberg of Microsoft and his team began working on a new language initially called COOL (C-like Object Oriented Language)  The name was eventually changed to C # by the time it was announced, along with Microsoft’s.NET, in 2000

6. History  James Gosling claimed that C # was an “imitation” of Java “[C # is] sort of Java with reliability, productivity and security deleted.”  Klaus Kreft and Angelika Langer (authors) “Java and C # are almost identical programming languages. Boring repetition that lacks innovation.”

7. History  However, over time Java and C # have taken different paths

8. Overview  Part of the.NET Framework  Compiler creates intermediate code (CIL)  CLR creates machine code  Just-in-time compilation

9. .exe or.dll  C # code can be compiled either to executable files or to library files (dynamically linked library) csc program.cs  compile to executable csc /t:library lib.cs  compile to dll

10. C like language  For the most part, if you have programmed in Java, C, C++ or any other C like language, you will be used to most C # syntax  C # uses {..} block statements  If else, while, do/while, for statements all the same  Even many keywords are the same (especially compared to Java)

11. Object Oriented  At the heart it is object oriented  Supports inheritance and polymorphism  Classes are like objects with members methods, constructors, etc.

12. Basic Program  The Main method static void Main() {…} static void Main(string[] args) {….} static int Main() {….} static int Main(string[] args) {…}  “Other overloaded versions of Main are permitted, however, provided they have more than one parameter, or their only parameter is other than type string[].” - Microsoft

13. Identifiers and Keywords  C # has 80 keywords  Some are context sensitive keywords They can be used as identifiers  All keywords are usable as identifiers if the @ symbol is in front of them @return, @null, @double int @int = 5; Console.WriteLine(@int);

14. Formatted Output  For output: Console.WriteLine(…..);  Format using {…} within a string {parameter #, spacing : special formatting}  Console.WriteLine(“{0,-10}.”, 100); > 100. ...WriteLine(“{1}, {0}”, firstName,lastName); >Rahimi, Shahram

15. Basic Programs

17. Types  Value Types sbyte, short, int, long, byte (unsigned), ushort, uint, ulong, char, float, double, decimal, bool Enum, Struct, Nullable  Reference Types Objects, string, class, interface, array, delegate

18. Arrays  Arrays are treated the same as in Java int[] n = new int[]{1,2,3,4}; SAME AS int[] n = {1,2,3,4}; SAME AS int[] n = new int[4]; n[0] = 1; …..

19. Types  Nullable type int?  allows the int values to also be null Useful for databases  Delegates A data structure that refers to one or more methods Similar to function pointers in C and C++

20. Delegates

22. Switch  Switch statements are mostly the same EXECPT that they require an explicit branch statement like break or goto due to a static semantic rule  Also, switch statements in C # allow strings along with int and char

23. Switch

24. Unsafe Code  While C # has made strides to eliminate the need for pointers as data types with references and objects, it is still allowed  One must declare unsafe code to: Declare and operate on pointers Perform conversions between pointers Take addresses of variables

25. Unsafe Code  Variables  Methods  Classes

26. Readability  Pro Basic syntax is C like (recognizable) Data must be explicitly typed and declared Very common special words and statement structure (loops and selection)  Con Not necessarily simple (delegates) Overloaded Main Keywords as identifiers All statements end with }

27. Writability  Pro Many ways to do one thing (like array declaration) Delegates can simplify method calling Inheritance  Con 80 keywords to remember (and required context)

28. Reliability  Pro Limits use of pointers, programmer becomes very aware of possible pointer issues. Uses explicitly typed and declared variables  Con Can write code in unsafe mode Can be a complex language

29. Cost Memory references and automatic garbage collection make creating quality code simpler and faster Uses Microsoft Visual Studio as compiler ○ Free open source versions are available, but premium versions can cost $2,000+ Similar to well known languages but can be a complex language

30. Who is using C # It’s Microsoft Who isn’t using it? Web design Gaming Medical Financial

31. Mono Project UNIX version of the Microsoft.NET development platform Open sourced based on C #.NET framework Enables Multi platform UNIX.NET applications Implements various technologies developed by Microsoft that have now been submitted to the ECMA for standardization.

32. Sources  “C # In Depth” – Jon Skeet  Wikipedia http://en.wikipedia.org/wiki/C_Sharp_(programming_langu age) http://en.wikipedia.org/wiki/C_Sharp_(programming_langu age)  “C sharp Language Specification” – Microsoft  “Concepts of Programming Languages” - Sebesta  “Essential C # 4.0” – Michaelis  http://www.mono-project.com/