This document discusses interfaces in object-oriented programming. It defines an interface as containing method signatures but no implementations, and classes implement interfaces by providing method bodies. The document outlines different types of inheritance, defines extending interfaces, and shows how a class can implement multiple interfaces. It provides an example of a class implementing two interfaces to demonstrate adding and multiplying values.

1. BABA GHULAM SHAH BADSHAH UNIVERSITY (RAJOURI)
AJEELA MUSHTAQ

2. BABA GHULAM SHAH BADSHAH
UNIVERSITY- RAJOURI (J&K).
DEPARTMENT OF COMPUTER
SCIENCES
PRESENTATION TOPIC:-
PRESENTED BY:-
Ajeela Mushtaq Roll NO:-13-Mcs-15
PRESENTED TO:-
MR MIRZA WASEEM
INTERFACES

3. OUTLINE :
• INHERITANCE
• TYPES
• INTERFACES
DEFINING AN INTERFACE
EXTENDING AN INTERFACE
IMPLEMENTING INTERFACES

4. Inheritance
• The mechanism of deriving a new class from an old one
is called inheritance.
• The old class is referred to as the base class and the
new one is called the derived class or sub-class.
• A derived class can inherits some or all of the traits
from the base class.

5. Types
• Single inheritance:
A derived class with only one base class is
called single inheritance.

6. • Multiple inheritance:
A derived class with several base classes is
called multiple inheritance.

7. • Multi-level inheritance:
The mechanism of deriving a class from
another ‘derived class’.

8. • Hierarchical inheritance:
A derived class in which the traits of one
class may be inherited by more than one class.

9. • This is combination of more than one inheritance.
• Hence, it may be a combination of Multilevel and
Multiple inheritance or Hierarchical and Multilevel
inheritance or Hierarchical , Multilevel and Multiple
inheritance.
Hybrid inheritance:

10. INTERFACE
• An interface can contain one or more
methods,properties,indexers and events but none of
them are implemented in the interface itself.
• It is the responsibility of the class that implements the
interface to define the code for implementation of these
members.

11. • Syntax
interface interfacename
member declarations

12. EXTENDING AN INTERFACE
• Like classes, interfaces can also be extended. That is,
an interface can be subinterfaced from other interfaces.
• The new subinterface will inherit all the members of the
superinterface in the manner similar to subclasses.
interface name2 : name1
members of name2

13. • Interfaces are allowed to extend other interfaces,
subinterfaces cannot define the methods declared in
the superinterfaces.
• It is the responsibility of the class that implements the
derived interface to define all the methods.
• It is important to remember that an interface cannot
extend classes.

14. IMPLEMENTING INTERFACES
• Interfaces are used as ‘superclasses’ whose properties
are inherited by classes.
• It is therefore necessary to create a class that inherits
the given interface.
class classname : interfacename
body of classname

15. • Here the class classname ‘implements’ the interface
interfacename. a more general form of
implementation may look like this :
class classname : superclass, interface1,
interface2….
body of class name
This shows that a class can extend another class while

16. using system;
interface Addition
int Add ();
interface Multiplication
int Mul ();
Class Computation : Addition, Multiplication
int x, y;
public Computation(int x, int y) //constructor
this.x = x;
this.y = y;
Public int Add () // implement Add ()
return (x + y);
Public int Mul () // implement Mul ()
return (x * y);
Class InterfaceTest1
public Static void Main()
computation com = new computation (10,20);
Addition add = (Addition) com;
//casting
Console.WriteLine (“Sum = “ + add.Add () );
Multiplication mul = (Multiplication) com;
//casting
Console.WriteLine(“Product = “ + mul.Mul () );

17. Output
sum = 30
product = 200

18. Properties….
• All the members of an interface are implicitly public
and abstract.
• An interface cannot contain constant fields ,constructors
and destructors.
• Its members cannot be declared static.
• Since the method in an interface are abstract, they do
not include implementation code.
• An interface can inherit multiple interfaces.

19. Thank you…!
Have a nice day
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