using System;

interface ExampleInterface

{

    void Display();

    //Error: Interfaces cannot have method definition only declaration

    //void Show()

    //{

    //    Console.WriteLine("This is an error");

    //}

}

abstract class Class1

{

    //Abstract class can contain abstract members

    //as wel as implemented members

    public abstract void Method1();

    public void MethodImplemented()

    {

        Console.WriteLine("Hello PRAGIM Technologies");

    }

}

using System;

interface ExampleInterface

{

    //Error: Interfaces cannot have fields

    //int i;

    //public ExampleInterface()

    //{

    //    Error: Interfaces cannot have constructors

    //}

    //~ExampleInterface()

    //{

    //    Error: Interfaces cannot have destructors

    //}

}

abstract class Class1

{

    //Abstract class can contain fields, constructors and destructors

    int i;

    public Class1()

    {

    }

    ~Class1()

    {

    }

}

using System;

interface ExampleInterface1

{

    void Display1();

    void Show1();

}

interface ExampleInterface2

{

    void Display2();

    void Show2();

}

abstract class Class1

{

    abstract public void Hide1();

}

abstract class Class2

{

    abstract public void Hide2();

}

//Error: MainClass cannot inherit from multiple classes

//at the same time.

//class MainClass : Class1, Class2

//{

//    public static void Main()

//    {

//        Console.WriteLine("Hello");

//    }

//}

//A class can inherit from multiple interfaces at the same time

class MainClass : ExampleInterface1, ExampleInterface2

{

    public static void Main()

    {

        Console.WriteLine("Hello");

        //MainClass must implement Display1(),Display2(),Show1() and Show2() methods.

    }

}

interface ExampleInterface

{

    //Error : Interface members cannot use access modifiers.

    //public void Display();

}

abstract class Class1

{

    //Abstract class members can use access modifiers.

    abstract public void Hide1();

}

• Class2 is inheriting from an abstract class Class1 and an interface ExampleInterface
• class2 implements only the inherited interface Display() method and not Hide1() method. So class2 is marked as abstract. so this proves that a class inheriting from an abstract class can either implement all base class abstract members or the class can be marked as abstract.

using System;

interface ExampleInterface

{

    void Display();

}

abstract class Class1

{

    abstract public void Hide1();

}

abstract class Class2 : Class1, ExampleInterface

{

    public void Display()

    {

        Console.WriteLine("Display() Method implemented");

    }

}

class MainClass : Class2

{

    public override void Hide1()

    {

        Console.WriteLine("Hide1() Method implemented");

    }

    public static void Main()

    {

        Console.WriteLine("Hello");

    }

}