1. Abstract Class cannot be instantiated.
2. An Abstract Class must be inherited.
3. It may have Concrete Methods.
4. It may have Abstract Methods.
5. An Abstract Method of an Abstract Class must be overridden.
6. An Abstract Class can only contain Abstract Method.
Abstract Class cannot be instantiated.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ExAbstract
{
abstract class sample
{
public sample()
{
Console.WriteLine( "Constructor of the Abstract Class" );
}
}
class Program
{
static void Main( string[] args )
{
sample p = new sample();
}
}
}
Error Message

An Abstract Class must be inherited
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ExAbstract
{
abstract class A
{
public A()
{
Console.WriteLine( "Abstract class Constructor" );
}
}
class B : A
{
}
class Program
{
static void Main( string[] args )
{
//A obj = new A();
B obj = new B();
Console.ReadLine();
}
}
}
Output:
Abstract Class may have Concrete Method
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ExAbstract
{
abstract class A
{
public A()
{
Console.WriteLine( "Abstract class Constructor" );
}
public void display()
{
Console.WriteLine( "This is a concrete method in Abstract Class" );
}
}
class B : A
{
}
class Program
{
static void Main( string[] args )
{
//A obj = new A();
B obj = new B();
obj.display();
Console.ReadLine();
}
}
}
Output:
Abstract Class may have Abstract Method
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ExAbstract
{
abstract class A
{
public A()
{
Console.WriteLine( "Abstract class Constructor" );
}
public void display()
{
Console.WriteLine( "This is a concrete method in Abstract Class" );
}
public abstract void display2();
}
class B : A
{
}
class Program
{
static void Main( string[] args )
{
//A obj = new A();
B obj = new B();
obj.display();
Console.ReadLine();
}
}
}
Error Message

An abstract method of an abstract class must be overridden
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ExAbstract
{
abstract class A
{
public A()
{
Console.WriteLine( "Abstract class Constructor" );
}
public void display()
{
Console.WriteLine( "This is a concrete method in Abstract Class" );
}
public abstract void display2();
}
class B : A
{
public override void display2()
{
Console.WriteLine( "An Abstract method is being overriden here" );
}
}
class Program
{
static void Main( string[] args )
{
//A obj = new A();
B obj = new B();
obj.display();
obj.display2();
Console.ReadLine();
}
}
}
An Abstract Method can be present only in Abstract Class

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