1.

What are sealed classes in C#?

Answer»

If we want to prevent any class from being inherited, it can be done with the help of a sealed keyword. So using a sealed keyword, a class denies the ability to create any child entity of this class, thereby calling itself a sealed class. If by mistake, a child of a sealed class is tried to be made, a compile-time error will occur.

using System;
// Sealed class
sealed class SealedClass
{
public int Add(int x, int y)
{
return x + y;
}
}
class Class1: SealedClass
{
static void Main(string[] args)
{
SealedClass sealedCls = new SealedClass();
int total = sealedCls.Add(4, 5);
Console.WriteLine("Total = " + total.ToString());
}
}

Compilation error:

prog.cs(12,7): error CS0509: `Class1': cannot derive from sealed type `SealedClass'
prog.cs(4,14): (Location of the symbol related to previous error)
Compilation failed: 1 error(s), 0 warnings


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