Download 1Introduction

Object Oriented Programming
Spring Semester 2012-13
Dr. Malik Jahan Khan
Department of Computer Science
Namal College
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Goals
• To introduce advance programming concepts
and techniques used in problem solving
including object oriented analysis, design and
implementation
• To enable object oriented modeling of any
unseen real life problem, and implementing
the solution
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Pre-Requisites
• Introduction to Programming
• Good problem solving abilities
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General Policies
• Additional to disciplinary policies of the institute /
university, plagiarism will be strictly dealt with.
Cheating any assignment, quiz or exam from any one
else may lead to severe penalty of grade. Violation of
rules / disturbance in class / involvement in plagiarism
may easily lead you to an “F” in the course. Both
parties involved in the plagiarism will be equally
punishable.
• Getting zero in a quiz, an exam problem or an
assignment is much better than cheating it from any
source. So avoid throwing yourselves in a very tensed
and harmful situation.
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General Policies (Cont.)
• Quizzes will be unannounced
• Project Deadlines Policy
• Detailed policies or changes in policies (if
needed) will be communicated with passage
of time.
• Sleeping in class is optional (not compulsory)!
• Latecomers?
• General Attitude Concern
– Zero tolerance policy on disciplinary issues
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Recommended Textbook
• Robert Lafore. “Object Oriented Programming
in C++”, 4th Edition, SAMS Publishing.
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Grading Policy
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Quizzes
Programming Projects
Midterm Exam
Final Exam
20%
20%
25%
35%
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Structured Programming
• We write series of steps to solve a problem
– Take input
– Perform certain manipulations
– Throw output
• If complexity grows, divide the program into
functions
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Shortcomings!
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This project is too complex!
The schedule slips
More programmers added in team
Complexity increases
Costs skyrocket
Schedule further slips
And disaster ensues
….
....
….
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Why All This Happens
• Functions have unrestricted access to all
global data
• Unrelated functions and data
• Poor model of the real world
– In real world, we have to deal with entities like
person, item, car, book, course, university etc
– None of these entities is like data
– None of these entities is like functions
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Solution
Object Oriented Programming!
But Why and How???
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Real World Modeling
• We deal with objects in real world like:
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People
Vehicles
Computers
Inventory Items
• By now, we know about data attributes (variables and
arrays etc)
• We also know about functions
• But the real word objects are neither like attributes nor
functions
• In fact, real word objects have both attributes and
some behavior (functions)
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Attributes
• Attributes are the characteristics of an object
• Examples
– People have eye color, name, job title, age, gender etc
– Cars have horsepower, number of doors, model, color
etc
• Attributes are like data members (variables etc.)
in a program, e.g.
– EyeColor (attribute) has value “blue”
– Age (attribute) has value “25”
– Model (attribute) has value “2003”
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Behavior
• Behavior is something a real world object does in
response to some stimulus
• Examples
– If you ask your boss for a raise, she will generally say
“YES” or “NO”
– If you apply brakes in a car, it will stop
• Here, saying something and stopping are
examples of behavior of two objects “boss” and
“car” respectively
• Behavior is like function, you call a function to do
something (e.g. stop the car, find factorial etc)
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So…..
• Attributes are represented by data like
variable, arrays, pointers etc
• Behavior is represented by functions
• But neither data nor functions, by themselves,
represent or model real world objects
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Object-Oriented Approach
• Fundamental idea behind OO approach is to
combine into a single unit both data and
functions that operate on that data
• Such a unit is called “object”
• Group of similar objects is called “class”
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How does a computer work?
• Hardware
– Central Processing Unit
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Hard disk
Processor
RAM
ROM
– Keyboard / Mouse
– Monitor
• Software
– System Software
• Operating Systems (MS Windows, Linux, Android etc)
• Device Drivers
– Application Software
• MS Office, Games, Internet Explorer, Your Programs…