Abstract Class in C#
An abstract method
has no implementation. Its implementation logic is provided instead by classes
that derive from it. We use an abstract class to create a base template for
derived classes.
Key Points:
Abstract classes have the following features:
- An abstract class cannot be instantiated.
- An abstract class may contain abstract methods and accessors.
- It is not possible to modify an abstract class with the sealed (C# Reference) modifier because the two modifers have opposite meanings. The sealedmodifier prevents a class from being inherited and the abstract modifier requires a class to be inherited.
- A non-abstract class derived from an abstract class must include actual implementations of all inherited abstract methods and accessors.
public abstract class Maths
{
public abstract int sum(int x, int y)
public int multiply(int x, int y)
{
return (x * y);
}
}
public class Test : Maths
{
public static void Main()
{
Test T = new Test();
Console.WriteLine("Enter value of X:");
int x = int.Parse(Console.ReadLine());
Console.WriteLine("Enter value of Y:");
int y = int.Parse(Console.ReadLine());
int Sum =
T.sum(x,y);
Console.WriteLine("SUM of " + x + "
and " + y + " IS:" + Sum);
int Multiply
= T.multiply(a, b);
Console.WriteLine("MULTIPLICATION of " + x + "
and " + y + " IS:" +
Multiply);
Console.Read();
}
public override int sum(int x, int y)
{
return (x + y);
}
}
