17 Kinds of Hello world!

Writing different "Hello World" programs using C #

1. A Beginners Hello World
public class HelloWorld
{
public static void Main ()
{
System.Console.WriteLine ("HELLO World");
}
}
2. Slightly improved version
Using System;

public class HelloWorld
{
public static void Main ()
{
Console.WriteLine ("HELLO World");
}
}
3. Command Line Arguments
Using System;

public class HelloWorld
{
public static void Main (string[] args)
{
Console.WriteLine (Args[0]);
}
}
4. From constructor
Using System;
public class HelloWorld
{
Public HelloWorld ()
{
Console.WriteLine ("HELLO World");
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();
}
}
5. More OO
Using System;
public class HelloWorld
{
public void HelloWorld ()
{
Console.WriteLine ("HELLO World");
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();
Hw. HelloWorld ();
}
}
6. From another class
Using System;
public class HelloWorld
{
public static void Main ()
{
Helloworldhelperclass HWH = new Helloworldhelperclass ();
Hwh.writehelloworld ();
}
}

public class Helloworldhelperclass
{
public void Writehelloworld ()
{
Console.WriteLine ("Hello World");
}
}
7. Inheritance
Abstract class Helloworldbase
{
public abstract void Writehelloworld ();
}
Class Helloworld:helloworldbase
{
public override void Writehelloworld ()
{
Console.WriteLine ("Hello World");
}
}
Class Helloworldimp
{
static void Main () {
Helloworldbase HWB = HelloWorld;
Helloworldbase.writehelloworld ();
}
}
8. Static Constructor
Using System;
public class HelloWorld
{
private static string Strhelloworld;

Static HelloWorld ()
{
Strhelloworld = "Hello World";
}
void Writehelloworld ()
{
Console.WriteLine (Strhelloworld);
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();
Hw.writehelloworld ();
}
}
9. Exception Handling
Using System;

public class HelloWorld
{
public static void Main (string[] args)
{
Try
{
Console.WriteLine (Args[0]);
}
catch (IndexOutOfRangeException e)
{
Console.WriteLine (E.tostring ());
}
}
}
Creating a DLL and using it in the application
Using System;

Namespace Hellolibrary
{
public class HelloMessage
{
public string Message
{
Get
{
Return "Hello, the world!!!";
}
}
}
}

//------

Using System;
Using Hellolibrary;

Namespace Helloapplication
{
Class HelloApp
{

public static void Main (string[] args)
{
HelloMessage m = new HelloMessage ();

}
}
}
Using Property
Using System;
public class HelloWorld
{
public string Strhelloworld
{
Get
{
Return to "Hello World";
}
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();
Console.WriteLine (Cs.strhelloworld);
}
}
Using delegates
Using System;
Class HelloWorld
{
static void Writehelloworld () {
Console.WriteLine ("HelloWorld");
}
static void Main () {
SimpleDelegate d = new SimpleDelegate (Writehelloworld);
D ();
}
}
Using Attributes
#define Debugging

Using System;
Using System.Diagnostics;

public class Helloworld:attribute
{
[Conditional ("debugging")]

public void Writehelloworld ()
{
Console.WriteLine ("Hello World");
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();

Hw.writehelloworld ();
}
}
Using interfaces
Using System;

Interface Ihelloworld
{
void Writehelloworld ();
}

public class Helloworld:ihelloworld
{
public void Writehelloworld ()
{
Console.WriteLine ("Hello World");
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();

Hw.writehelloworld ();
}
}
Dynamic Hello World
Using System;
Using System.Reflection;

Namespace Helloworldns
{

public class HelloWorld
{
public string Writehelloworld ()
{
return "HelloWorld";
}

public static void Main (string[] args)
{
Type HW = Type.GetType (args[0]);

Instantiating a class dynamically

object[] Nctorparams = new object[] {};
Object nobj = Activator.CreateInstance (HW,
Nctorparams);

Invoking a method

object[] Nmthdparams = new object[] {};
String Strhelloworld = (string) hw. InvokeMember (
"Writehelloworld", Bindingflags.default |
BindingFlags.InvokeMethod, NULL,
Nobj, Nmthdparams);

Console.WriteLine (Strhelloworld);
}
}
}
Unsafe Hello World
Using System;

public class HelloWorld
{
unsafe public void Writehelloworld (char[] chrarray)
{
Fixed (char *parr = chrarray)
{
char *pch = Parr;
for (int i=0; i<chrarray.length; i++)
Console.Write (* (pch+i));
}
}

public static void Main ()
{
HelloWorld HW = new HelloWorld ();
char[] Chrhelloworld = new char[]
{' H ', ' e ', ' l ', ' l ', ' o ', ', ' W ', ' o ', ' r ', ' L ', ' d '};
Hw.writehelloworld (Chrhelloworld);
}
}
-Using InteropServices
Using System;
Using System.Runtime.InteropServices;

Class Class1
{
[DllImport ("kernel32")]
private static extern int Beep (int dwfreq, int dwduration);

static void Main (string[] args)
{
Console.WriteLine ("Hello World");
Beep (1000, 2000);
}
}