C# (pronounced C sharp) is an object-oriented programming language developed by Microsoft as part of their .NET initiative.

Microsoft based C# on C++ and the Java programming language. Some languages sacrifice RAD (Rapid Application Development) conveniences for power and low-level control. C# was designed as balance between power and development speed.

Table of contents

1 Program execution
2 Standardization
3 Example
4 External links

Program execution

C# does not compile to binary code which can be executed directly by the target computer. Instead, as with Java, it is compiled to an intermediary code which is executed on a virtual machine which is included in the .NET framework. All .NET languages (which includes Visual Basic .NET and Managed C++ as well as C#) compile to this intermediary code called Microsoft Intermediate Language (MSIL). To the casual observer, the resulting program looks like a normal executable and has an ".exe" extension just like a normal application. However, executing the program fails on a computer that does not have the .NET Framework installed.

When the program is executed, the .NET framework compiles the intermediate code into binary code as it is run—just-in-time compilation (JIT). The resulting binary code is stored temporarily (in a memory cache), so if the program uses that portion of code again, the cached version is used. However this is only in effect during the runtime of the program. If a .NET application is run again, this compilation process is done again.

Standardization

Microsoft has submitted C# to the ECMA for formal standardization. In December 2001, ECMA released ECMA-334 C# Language Specification. C# became an ISO standard in 2003 (ISO/IEC 23270). There are independent implementations being worked on, including:

Ximian's open source .NET implementation, Mono
the Free Software Foundation's dotGNU Portable.NET

More recently, Microsoft has announced plans to add support for generics, templates, partial types and some other new features. Those additions were already proposed for ECMA/ISO standardization.

Example

using System;
namespace Example
{
    public class HelloWorld
    {
        private String aString;

        public HelloWorld()
        {
            aString = "Hello World";
        }

        public override String ToString()
        {
            return(aString);
        }

        public static void Main()
        {
            HelloWorld aHelloWorld = new HelloWorld();
            Console.WriteLine(aHelloWorld.ToString());
        }
        //Output is:Hello World
    }
}