Object Oriented Programming Spring Semester 2012 13 Dr

Object Oriented Programming Spring Semester 2012 -13 Dr. Malik Jahan Khan Department of Computer Science Namal College 1

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 2

Pre-Requisites • Introduction to Programming • Good problem solving abilities 3

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. 4

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 5

Recommended Textbook • Robert Lafore. “Object Oriented Programming in C++”, 4 th Edition, SAMS Publishing. 6

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Grading Policy • • Quizzes Programming Projects Midterm Exam Final Exam 20% 25% 35% 8

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 9

Shortcomings! • • This project is too complex! The schedule slips More programmers added in team Complexity increases Costs skyrocket Schedule further slips And disaster ensues …. . . …. 10

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 11

Solution Object Oriented Programming! But Why and How? ? ? 12

Real World Modeling • We deal with objects in real world like: – – 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) 13

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. – Eye. Color (attribute) has value “blue” – Age (attribute) has value “ 25” – Model (attribute) has value “ 2003” 14

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) 15

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 16

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” 17

How does a computer work? • Hardware – Central Processing Unit • • 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…