Nullable Type In C# with Example


IN THIS  POST WE WILL LEARN 



  1. NULLABLE TYPE IN C# 
  2. NULL COALESCING  OPERATOR  ??  
Type in C#

In C# types are divided into 2 broad Categories

Reference Types :  Interface , Class , Delegates , Arrays E.t.c
Value Types        : Int , Float , Double , Structs ,Enums E.t.c

By Default value types are non nullable. To make then nullable Use   ?

int r= 0 (r is non nullable, so r cannot be set null , r= null will generate Error )

int? m =0 (m is nullable int , so m=null is legal)


Example :  Nullable Type  In C#


  2. using System;


  5. namespace NullableTypeInCshape
  6. {
  7.     class Program
  8.     {
  9.         static void Main(string[] args)
  10.         {

  12.             bool? AreYouvirgin = true;

  14.             if (AreYouvirgin ==true)
  15.             {
  16.                 Console.WriteLine("Yes I am virgin ");
  17.                 
  18.             }
  19.             else if (AreYouvirgin == false)
  20.             {
  21.                  Console.WriteLine("Yes I am Not virgin  "); 
  22.             }
  23.             else
  24.             {
  25.                 Console.WriteLine(" Use Can Not Given Answer");

  27.             }

  29.             Console.ReadLine();
  30.         }
  31.     }
  32. }
         Output :



2. NULL COALESCING  OPERATOR  ??  


 Example :   With Out Null Coalescing Operator
  • using System;


  • namespace NullableTypeInCshape
  • {
  •     class Program
  •     {
  •         static void Main(string[] args)
  •         {

  •             int? RoomOnSale = null;
  •             int AvaialableRoom;

  •             if (RoomOnSale ==null)
  •             {
  •                 AvaialableRoom = 0; 
  •             }
  •             else
  •             {
  •                 AvaialableRoom = RoomOnSale.Value;
  •             }
  •             Console.WriteLine("AvaialableRoom={0}", AvaialableRoom);


  •         }
  •     }
  • }

  •


     Example :  Using  Null Coalescing Operator


  • using System;


  • namespace NullableTypeInCshape
  • {
  •     class Program
  •     {
  •         static void Main(string[] args)
  •         {

  •             int? RoomOnSale = null;
  •             int AvaialableRoom = RoomOnSale ??0;//  Using sing  Null Coalescing Operator 

  •            
  •             Console.WriteLine("AvaialableRoom={0}", AvaialableRoom);

  •             Console.ReadLine();

  •         }
  •     }
  • }

    •
    Output:
     




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