The Anatomy of a Basic C# Application                              

C# demands that all program logic be contained within a type definition.  Recall that a type is a term that refers
to a class, interface, structure, enumeration, or delegate.  Unlike C++, it is not possible to create global functions
or global points of data in C#. All logic must be within a type definition.   

Every C# application must contain a class defining a Main() method that provides the entry point for the
application.  A Main() method must be declared static, which will be formally defined later.  

In its simplest form, a C# application can be defined as follows:


// C# source files end with a *.cs file extension.
using System;

class HelloWorld
{
  static void Main()
  {
     Console.WriteLine("Hello World!");        
  }
}



C# accepts other variations of Main():


// No return, no arguments.
static void Main()
{
  // Do stuff.
}



// No return, no arguments.
static void Main()
{
  // Do stuff.
}



// Integer return type, no arguments.
static int Main()
{
  // Do stuff.

  // Return an integer to the system. By convention, returning 0
  // indicates success. Anything else indicates an error code.
  return 0;
}



// Integer return type, get command line args.
static int Main(string[] args)
{
  // Process command line arguments.
  // Do stuff.
  // Return a value to the system.
  return 0;
}


This example processes the command line arguments passed into Main() as a string array called args.


class HelloWorld
{
  static int Main(string[] args)
  {
     // Do we have any arguments?
     for(int x = 0; x < args.Length; x++)
     {
        Console.WriteLine("Arg: {0}", args[x]);
     }
                                       
     Console.WriteLine("Hello World!");
     return 0;
  }
}


Also be aware that Main() can be declared public or private.  In fact, given that private is the default access
modifier in C# for type member, each of the Main() methods you just examined were in fact private.
The Anatomy of a Basic C# Application
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