Lecture slides by:
A new paradigm                        Farhan Amjad
of programming
 After   this lecture, you should be able to
    Difference of OO technique by other techniques
    Understand the mean...
OOPS

It’s OOP not OOPS
   Detailed Course Outline is on the subject homepage
      http://groups.google.com/group/sp09_bcs2
Check your email oft...
   Recommended Books:
       OOP using C++ 6th Edition, Prentice Hall
   Reference Books:
       OOP in C++ by Robert ...
But not in Class. What
you have to do is just
inform me about your
situation and I will not
mark your absent.
Course Policy
 Applicablerules and submission deadlines will
 be indicated with the assignments

 No   make-ups
   10-15 minutes duration

   Will cover reading assignments and
    material covered in the class

   Unannounced

  ...
    Supervised Lab Sessions and Tutorials will be
    organized as and when required.
I   will ask questions very often
    So be attentive
 Actually,  programming is not so
  easy, because a real good program is not
  easily programmed. It needs the
  programm...
 Usually,people start learning
 programming by writing small
 and simple programs
 consisting only of one main      Main ...
 This programming technique can only be used in
  a very small program.
 For example, if the same statement sequence is
...
 With  procedural programming,     Main
                                             Procedure
  you are able to combine ...
 Programs  can now be written more
  structured and error free.
 For example, if a procedure is
  correct, every time it...
 Now  a program can be viewed as a sequence of
  procedure calls.
 The main program is responsible to pass data to
  the...
Main Program
                Data


Procedure1     Procedure2   Procedure3
 Modular  programming is subdividing your
  program into separate subprograms such as
  functions and subroutines.
 With...
Main Program(Also a module)

                                     Data




            Module1                            ...
 Each  module can have its own data. This allows
  each module to manage an internal state which
  is modified by calls t...
 Also structured programming
 A subset of procedural programming that
  enforces a logical structure on the program
  be...
Global Data        Global Data         Global Data




  Function    Function      Function      Function
 When  the program grows larger and more
  complex even the structural programming
  shows the strain.
 You may have hea...
 It   is a kind of thinking methodology
      Everything in the world is an object;
      Any system is composed of obj...
   Build programming using software objects.
   Means that we organize software as a
    collection of discrete (differe...
A  flower, a tree, an animal
 A student, a professor
 A desk, a chair, a classroom, a building
 A university, a city, ...
A  law system
 A cultural system
 An educational system
 An economic system
 An Information system
 A computer system
 University   is developed by the interactions
 among:
    students
    professors
    staffs
    officers of Bio-sci...
   ADTs allows the creation of instances with well-defined
    properties and behavior.
    In object-orientation, ADTs ...
Object1

                          Data1+Procedures1




      Object2

Data2 + Procedures2 1
               Data
        ...
 An object-based programming language is one
  which easily supports object-orientation.
 Smalltalk:1972-1980, Alan Kay
...
◆   Complexity & Haste:
   Skilled programmer: 10-15 lines of code a day
   Price ~ $18/line
   Can you pay this? If n...
 Reduce    development cost:
    one component instead of many
 Promote    reliability:
    exercise component from ma...
    INFO TECH RESEARCH FUNDING
     The Clinton Administration has targeted 5
     technology areas for support from the ...
 Adding new features responding to changing
  operation environment can be a matter of
  introducing a few new objects.
...
   Flexibility
    Very flexible in accommodating different
    situations because the interaction patterns
    among the...
 Data is more important then
  functions, methods, procedures etc but in
  procedural languages data is given the
  secon...
 Reduces  complexity much like the detailed
  workings of an automobile are hidden from
  the average driver.
 Principle...
Classes
Objects
Data encapsulation
Inheritance
Polymorphism
   Class
     A generic definition for a set of similar
      objects.
     Provides the specifications for the
      o...
The key concepts are:
 Object
   Directly relate to the real world entities.
   Can be a person, thing or concept.
   ...
Object vs Class
 object is created from a class.
 object is considered as an instance of a class.
 class is considered ...
Object vs Class
Diagram 1: Class Car   Diagram 2: MyCar as an Object

        Car


    Door
    Seat
    Type
    Model

...
Messages
 Requests for the receiver objects to carry
  out the indicated method or behavior and
  return the result of th...
   Encapsulation
     Process of hiding the implementation
      details of an object.
     Access to manipulate the ob...
   Encapsulation (cont)
     Program maintenance is easier and less
      expensive because changes in the
      object ...
   Inheritance
     Code reuse mechanism to build new
      objects out of old ones.
     Defines a relationship among ...
   Polymorphism
     Means having many forms.
     Provides the ability to use a single
      message to invoke many di...
 Protected    levels in a class:
     Public: Can be accessed both within and external
      to the object.
     Privat...
 What   is Object Oriented Programming?
 Object-oriented programming is a method
  of implementation in which programs a...
 OOP  by Robert Lafore
 OOP by Deitel and Deitel
 Haibin Zhu, Ph. D. Associate Professor of CS,
  Nipissing University
...
Introduction to object oriented language
Introduction to object oriented language
Introduction to object oriented language
Introduction to object oriented language
Introduction to object oriented language
Introduction to object oriented language
Introduction to object oriented language
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Introduction to object oriented language

  1. 1. Lecture slides by: A new paradigm Farhan Amjad of programming
  2. 2.  After this lecture, you should be able to  Difference of OO technique by other techniques  Understand the meaning of object  Know the difference between an object and a class  Know the concepts of object orientation  Understand how objects communicate
  3. 3. OOPS It’s OOP not OOPS
  4. 4.  Detailed Course Outline is on the subject homepage http://groups.google.com/group/sp09_bcs2 Check your email often for announcements related to the course
  5. 5.  Recommended Books:  OOP using C++ 6th Edition, Prentice Hall  Reference Books:  OOP in C++ by Robert Lafore  Thinking in C++, 2nd Edition, by Bruce Eckel
  6. 6. But not in Class. What you have to do is just inform me about your situation and I will not mark your absent.
  7. 7. Course Policy
  8. 8.  Applicablerules and submission deadlines will be indicated with the assignments  No make-ups
  9. 9.  10-15 minutes duration  Will cover reading assignments and material covered in the class  Unannounced  No make-ups
  10. 10.  Supervised Lab Sessions and Tutorials will be organized as and when required.
  11. 11. I will ask questions very often  So be attentive
  12. 12.  Actually, programming is not so easy, because a real good program is not easily programmed. It needs the programmers’ lots of wisdom, lots of knowledge about programming and lots of experience.  It is like writing, to be a good writer needs lots of experience and lots of knowledge about the world.  Learning and practice are necessary.
  13. 13.  Usually,people start learning programming by writing small and simple programs consisting only of one main Main Program program. Here ``main program'' stands for a Data sequence of commands or statements which modify data which is global throughout the whole program.
  14. 14.  This programming technique can only be used in a very small program.  For example, if the same statement sequence is needed at different locations within the program, the sequence must be copied. If an error needed to be modified, every copy needs to be modified.  This has lead to the idea to extract these sequences(procedure), name them and offering a technique to call and return from these procedures.
  15. 15.  With procedural programming, Main Procedure you are able to combine Program sequences of calling statements into one single place.  A procedure call is used to invoke the procedure. After the sequence is processed, flow of control proceeds right after the position where the call was made .
  16. 16.  Programs can now be written more structured and error free.  For example, if a procedure is correct, every time it is used it produces correct results.  Consequently, in cases of errors you can narrow your search to those places which are not proven to be correct.
  17. 17.  Now a program can be viewed as a sequence of procedure calls.  The main program is responsible to pass data to the individual calls, the data is processed by the procedures and the resulting data is presented.  Thus, the flow of data can be illustrated as a hierarchical graph, a tree.
  18. 18. Main Program Data Procedure1 Procedure2 Procedure3
  19. 19.  Modular programming is subdividing your program into separate subprograms such as functions and subroutines.  With modular programming, procedures of a common functionality are grouped together into separate modules.  A program therefore no longer consists of only one single part. It is now divided into several smaller parts which interact through procedure calls and which form the whole program.
  20. 20. Main Program(Also a module) Data Module1 Module2 + + Data Data11 Data Data Data2 Procedure1 Procedure2 Procedure3 The main program coordinates calls to procedures in separate modules and hands over appropriate data as parameters.
  21. 21.  Each module can have its own data. This allows each module to manage an internal state which is modified by calls to procedures of this module.  Each module has its own special functionalities that supports the implementation of the whole program.
  22. 22.  Also structured programming  A subset of procedural programming that enforces a logical structure on the program being written to make it more efficient and easier to understand and modify.  Certain languages such as Ada, Pascal, and dBASE are designed with features that encourage or enforce a logical program
  23. 23. Global Data Global Data Global Data Function Function Function Function
  24. 24.  When the program grows larger and more complex even the structural programming shows the strain.  You may have heard horror stories of project’s complexity, schedule slipping etc.  In procedural programming data is given second class status. Inventory system-> new programmer->writes the function It is same like you are sitting in your lobby and left there your personal documents.
  25. 25.  It is a kind of thinking methodology  Everything in the world is an object;  Any system is composed of objects (certainly a system is also an object);  The evolution and development of a system is caused by the interactions among the objects inside or outside the system
  26. 26.  Build programming using software objects.  Means that we organize software as a collection of discrete (different) objects that incorporate both data structure and behavior.  In OOP, the software objects correspond closely to real objects involve in the application area.
  27. 27. A flower, a tree, an animal  A student, a professor  A desk, a chair, a classroom, a building  A university, a city, a country  The world, the universe  A subject such as CS, IS, Math, History, …
  28. 28. A law system  A cultural system  An educational system  An economic system  An Information system  A computer system
  29. 29.  University is developed by the interactions among:  students  professors  staffs  officers of Bio-science  officers of CIIT  … ...
  30. 30.  ADTs allows the creation of instances with well-defined properties and behavior.  In object-orientation, ADTs are referred to as classes.  Therefore, a class defines properties of objects which are the instances in an object-oriented environment.  Object-oriented programming is ``programming with ADTs'': combining functionality of different ADTs to solve a problem.  Therefore instances (objects) of ADTs (classes) are dynamically created, destroyed and used.
  31. 31. Object1 Data1+Procedures1 Object2 Data2 + Procedures2 1 Data Object3 Data3 + Procedures3 Object4 Data4 + Procedures4
  32. 32.  An object-based programming language is one which easily supports object-orientation.  Smalltalk:1972-1980, Alan Kay  C++:1986, Bjarne Stroustrup  Java:1992 (Smalltalk + C++), James Gosling  C#:  Developed at Microsoft by Anders Hejlsberg et al, 2000  Event driven, object oriented, visual programming language (C++ and Java)
  33. 33. ◆ Complexity & Haste:  Skilled programmer: 10-15 lines of code a day  Price ~ $18/line  Can you pay this? If not, what will you do?  Hire non professionals? ◆ OOP fights Complexity:  A more realistic model of the world  Collection of interacting objects instead of a collection of functions  Reuse of ready made components
  34. 34.  Reduce development cost:  one component instead of many  Promote reliability:  exercise component from many different aspects  noneed to remember to correct the same error twice
  35. 35.  INFO TECH RESEARCH FUNDING The Clinton Administration has targeted 5 technology areas for support from the National Institute of Standards & Technology, and two focus directly on information technology: a nationwide health care information infrastructure and an effort to develop reusable software components for large software systems. [Wall Street Journal, 26 April ‘94, Page B6] Reuse is tightly coupled with abstraction: ● Identify similarity between elements. ● Create a component that represents the similar parts. ● Rewrite elements to use the common part.
  36. 36.  Adding new features responding to changing operation environment can be a matter of introducing a few new objects.  Easy to make minor changes in the data representation/ the procedures used in an OO program. Changes within an object do not affect any other parts of the program.
  37. 37.  Flexibility Very flexible in accommodating different situations because the interaction patterns among the object can be changed without modifying the object.  Maintainability Objects can be maintained separately. Reusability  Objects can be reused in the different programs.
  38. 38.  Data is more important then functions, methods, procedures etc but in procedural languages data is given the second class status. OOP also provides the mechanism to hide the data.  Example:  Importance of data in inventory system, banking system etc.  You hire a new programmer and he accidently changes the corrupts the data. Same like someone changes your personal data.
  39. 39.  Reduces complexity much like the detailed workings of an automobile are hidden from the average driver.  Principle of least privilege (need-to-know)  More Secure. Less likely that someone will alter or misuse something.  Easier to change the implementation without affecting other modules that use it.
  40. 40. Classes Objects Data encapsulation Inheritance Polymorphism
  41. 41.  Class  A generic definition for a set of similar objects.  Provides the specifications for the objects’ behaviors and attributes.  An abstraction of a real world entity.
  42. 42. The key concepts are:  Object  Directly relate to the real world entities.  Can be a person, thing or concept.  Like a “black box”, therefore all the implementation is hidden.  Has a  State (attribute)  Behavior (operation)  Identity (unique name)
  43. 43. Object vs Class  object is created from a class.  object is considered as an instance of a class.  class is considered as a template from which objects are instantiated  can create an object or many objects from a class.
  44. 44. Object vs Class Diagram 1: Class Car Diagram 2: MyCar as an Object Car Door Seat Type Model Drive Stop Lock Unlock
  45. 45. Messages  Requests for the receiver objects to carry out the indicated method or behavior and return the result of that action to the sender objects
  46. 46.  Encapsulation  Process of hiding the implementation details of an object.  Access to manipulate the object data is through its interface (operations/ functions).  Protects an object’s internal state from being corrupted by other programs.
  47. 47.  Encapsulation (cont)  Program maintenance is easier and less expensive because changes in the object data or implementation is only modified in one place  Allows objects to be viewed as black boxes.
  48. 48.  Inheritance  Code reuse mechanism to build new objects out of old ones.  Defines a relationship among classes where one class shares the structure and/or behavior on one or more classes.  Provides a more flexible and adaptable system and enables polymorphism.
  49. 49.  Polymorphism  Means having many forms.  Provides the ability to use a single message to invoke many different kinds of behavior.  Same name with different meaning.
  50. 50.  Protected levels in a class:  Public: Can be accessed both within and external to the object.  Private: Can only be used by the object itself.  The public section of a class is usually called the interface. It is what the programmers sees.  Normally, All data is private and only the bare essential functions are made public.
  51. 51.  What is Object Oriented Programming?  Object-oriented programming is a method of implementation in which programs are organized as cooperative collections of objects, each of which represents an instance of some class, and whose classes are all members of one or more hierarchy of classes united via inheritance relationships
  52. 52.  OOP by Robert Lafore  OOP by Deitel and Deitel  Haibin Zhu, Ph. D. Associate Professor of CS, Nipissing University  Complete Reference
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