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C# Nullable

In C#, Nullable is a concept that allows a type to hold an additional value null. In other words, we can make a variable Nullable, so, it can hold additional null value. All Nullable variables are the instances of System.Nullable<T> struct.

The concept of Nullable is useful when we deal with databases that contain elements that may not be assigned a value.

C# provides two different ways to create Nullable types.

  1. By creating System.Nullable instance,
  2. By using ? operator

Note: we cannot create Nullable of reference type variable.


C# System.Nullable Example

In the following example, we are making Nullable with the help of System.Nullable namespace.

// NullableExample2.cs

Output:

Compile the program by using the following command.

csc NullableExample2.cs

Csharp Nullable 1

Run the program by using following command.

NullableExample2.exe

Csharp Nullable 2

C# Nullable using ? Operator Example 1

There is no significant difference between using of either System.Nullable or ? operator. We can use anyone as per our comfort.

// NullableExample.cs

Output:

10
a contains null value

C# Nullable using ? Operator Example 2

Output:

10
It contains null value





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B.Tech / MCA