Amy Broom Hossam Ragaban Randal Rollings

1. C# Amy Broom Hossam Ragaban Randal Rollings Fall 2003

2. History • The history of C# begins early in 1970’s when C was invented in which UNIX was written. But C had some drawbacks. The power that C affords the programmer makes it easy for him to blunder. For example, it allows the programmer to directly allocate memory and permits him to deallocate this memory. • Then came C++ in the 1980’s, who like its predecessor took the world by a storm. Despite it being object-oriented C++ had some problems. Veteran programmers often had problems migrating from C (structured) to C++ ( object-oriented ) because effective C++ programming requires a completely new mindset. 

3. More History • Sun created Java. They were motivated with the World Wide Web. They sought a single environment that would target multiple platforms. Programs in Java are not compiled to machine code, but instead to an intermediate language or bytecode that can be executed on any computer equipped with a suitable interpreter program (The Java Runtime).  • Today, Microsoft unveils an alternative strategy for bringing the development and web worlds together and online with .NET. Because all .NET languages compile to a common bytecode, a developer can program in whichever language he wants and share his works with other developers using other .NET languages. 

4. Even More History In June 2000, Microsoft announced both the .NET platform and a new programming language called C#. C# is a strongly-typed object-oriented language designed to give the optimum blend of simplicity, expressiveness, and performance. The .NET platform is centered around a Common Language Runtime (similar to a JVM) and a set of libraries which can be exploited by a wide variety of languages which are able to work together by all compiling to an intermediate language (IL). C# and .NET are a little symbiotic: some features of C# are there to work well with .NET, and some features of .NET are there to work well with C# (though .NET aims to work well with many languages). The C# language was built with the hindsight of many languages, but most notably Java and C++. It was co-authored by Anders Hejlsberg (who is famous for the design of the Delphi language), and Scott Wiltamuth.

5. Common Language Runtime • The CLR serves as an execution engine for applications. • Every byte of code that you write for the framework runs in the CLR. • CLR consists of instructions written in CIL(common intermediate language-pseudo-machine language). CIL instructions are just-in-time and compiled into native machine code at run time. • A given method is compiled only once-the first time it is called-and thereafter cached in memory so it can be executed again without delay.

6. Advantages This robust development package, which uses the component oriented C# development language, offers beginning and intermediate developers with C++ or Java experience a modern language and environment for creating next-generation software. Visual C# .NET 2003 delivers superior functionality for streamlining business processes, including: • Rapid design, development, and deployment support for creating and consuming Web services. • Form designers and visual controls for creating rich Windows-based applications. • Authoring tools and services for building powerful Microsoft .NET server-based solutions. • Migration tools for converting Java-based projects to the Microsoft .NET development environment

7. Advantages With Visual C# .NET 2003, developers can build solutions for a wide range of clients; including Windows, the Web, and mobile or embedded devices. Using this elegant programming language and its tools, developers can leverage their existing C++ and Java-language skills and knowledge to be successful in the .NET environment.

8. Improvements C# offers significant improvements including: unified type system, powerful new language constructs which are easily understood by developers, and “unsafe” code of maximum developer control. The language provides inherent support for properties, indexers, versioning, operator overloading, delegates, and custom attributes.

9. C# and Java Similarities • Compiles into machine-independent language-independent code which runs in a managed execution environment. • Garbage Collection coupled with the elimination of pointers (in C# restricted use is permitted within code marked unsafe) • No header files, all code scoped to packages or assemblies, no problems declaring one class before another with circular dependencies • Classes all descend from object and must be allocated on the heap with new keyword • Thread support by putting a lock on objects when entering code marked as locked/synchronized • Interfaces, with multiple-inheritance of interfaces, single inheritance of implementations • Inner classes

10. C# and Java Similarities cont. • No concept of inheriting a class with a specified access level • No global functions or constants, everything belongs to a class • Arrays and strings with lengths built-in and bounds checking • The "." operator is always used, no more ->, :: operators • null and boolean/bool are keywords • All values are initialized before use • Try Blocks can have a finally clause

11. Main Features • Pointers are missing in C#. • Unsafe operations such as direct memory manipulation are not allowed. • In C# there is no usage of "::" or "->" operators. • Since it`s on .NET, it inherits the features of automatic memory management and garbage collection. • Integer values of 0 and 1 are no longer accepted as boolean values.Boolean values are pure true or false values in C# so no more errors of "="operator and "=="operator. "==" is used for comparison operation and "=" is used for assignment operation.

12. Testing and Debugging Testing and debugging tools are of the languages features providing a powerful remote and multi-language debugger that allows developers to test applications and build reliable multi-tier solutions that span process boundaries and are written in multiple programming languages.

13. Delegates A delegate can be thought of as a type-safe object- oriented function pointer, which is able to hold multiple methods rather than just one. Delegates handle problems which would be solved with function pointers in C++, and interfaces in Java. It improves on the function pointer approach by being type safe and being able to hold multiple methods. It improves on the interface approach by allowing the invocation of a method without the need for inner-class adapters or extra code to handle multiple-method invocations.

14. Events C# provides direct support for events. Although event handling has been a fundamental part of programming since programming began, there has been surprisingly little effort made by most languages to formalize this concept. If you look at how today's mainstream frameworks handle events, we've got examples like Delphi's function pointers (called closures), Java's inner class adaptors, and of course, the Windows API's message system. C# uses delegates along with the event keyword to provide a very clean solution to event handling.

15. Properties • Properties will be a familiar concept to Delphi and Visual Basic users. The motivation is for the language to formalize the concept of getter/setter methods, which is an extensively used pattern, particularly in RAD (Rapid Application Development) tools. • This is typical code you might write in Java or C++: foo.setSize (getSize () + 1); label.getFont().setBold (true); • The same code you would write like this in C#: foo.size++; label.font.bold = true;

16. Polymorphism Virtual methods allow object oriented languages to express polymorphism. This means a derived class can write a method with the same signature as a method in its base class, and the base class will call the derived class's method. By default in Java, all methods are virtual. In C#, like C++, the virtual keyword must be used so that the method will be called by the base class.

17. Foreach Statement C# provides a shorthand for for-loops: • In Java or C++: for (int i = 0; i < array.length; i++)... • In C#: foreach (int i in array)...

18. Bibliography • http://msdn.microsoft.com/vcsharp/productinfo/features/default.aspx • http://genamics.com/developer/csharp_comparative.htm • http://www.csharphelp.com/archives/archive55.html • http://www.funducode.com/csharp/basics/basics1.htm • http://msdn.microsoft.com/vcsharp/productinfo/overview/default.aspx