Editing Immutable object (section)

=== C# ===
In [[C Sharp (programming language)|C#]] you can enforce immutability of the fields of a class with the <code>readonly</code> statement.<ref name=Skeet>{{cite book |last=Skeet|first=Jon|title= C# in Depth |date=23 March 2019 |publisher= Manning |isbn= 978-1617294532}}</ref>{{rp|239}}
By enforcing all the fields as immutable, you obtain an immutable type.

<syntaxhighlight lang="csharp">
class AnImmutableType
{
    public readonly double _value;
    public AnImmutableType(double x) 
    { 
        _value = x; 
    }
    public AnImmutableType Square() 
    { 
        return new AnImmutableType(_value * _value); 
    }
}
</syntaxhighlight>

C# have records which are immutable.<ref>{{cite web |title=Use record types - C# tutorial - C# |url=https://learn.microsoft.com/en-us/dotnet/csharp/tutorials/records |website=learn.microsoft.com |access-date=23 February 2024 |language=en-us |date=14 November 2023}}</ref><ref>{{cite web |title=Records - C# reference - C# |url=https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/record |website=learn.microsoft.com |access-date=23 February 2024 |language=en-us |date=25 May 2023}}</ref>
<syntaxhighlight lang="csharp">
record Person(string FirstName, string LastName);
</syntaxhighlight>