045 C# Keywords

Keyword  
C#  keywords  are predefined and reserved for a language usage.Each keyword  have its own meaning and instruction to the compiler. If you use the same name identifier, it will conflict and  throw error. You can use the same name of a keyword  adding @ at the start of a identifier name.

Here  is the example of how error occurred  if we use same name identifier and keyword.
Example 1

using System;

using System.Collections.Generic;

using System.Text;

namespace ConsoleApplication1

{

           class Program

           {

                     static void Main(string[] args)

                   {

                         student case = new student();

                    }

          }

          class student

         {

              string Name;

             int Roll_Number;

          }

}

Output :Error

Invalid expression term 'case'    

Here 'case' is reserve keyword , we used as identifier , causes error.

Here is the example how we can use same name identifier and keyword without error.

Example 1

using System;

using System.Collections.Generic;

using System.Text;

namespace ConsoleApplication1

{

                  class Program

                 {

                        static void Main(string[] args)

                        {

                                   student @case = new student();

                         }

                 }

               class student

               {

                 string Name;

                 int Roll_Number;

             }

}



There are two types of Keyword, reserve and contextual.

 

Here is the list of reserved keyword commonly used.

abstract	explicit	const	event
return	new	override	extern
readonly	sealed	static	unsafe
virtual	volatile	public	private
internal	protected	if	else
switch	case	do	foreach
in	while	break	continue
default	goto	throw	try
catch	finally	unchecked	checked
fixed	lock	ref	out
using	awit	true	enum
void	bull	bite	case
class	decimal	int	double
float	string	unit	sbyte
struc	long	double

Contextual keyword : keyword are valid for certain context only. This keyword are not reserved, are reserved for certain context only.

add	async	await	dynamic
get	global	partial	remove
set	value	var	when
where	yield

Here is the example of contextual keyword , 'global' keyword here used for current context only.

Example 1

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace ConsoleApplication1

{

          class Program

         {

             static void Main(string[] args)

              {

                        global::System.Console.WriteLine("Your Specific Text");

                         Console.ReadKey();

             }

        }

     class System

     {

      }

}