Absolute Beginner's Guide To Object Oriented Programming

User Manual:

Open the PDF directly: View PDF PDF.
Page Count: 11

11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 1 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
Absolute Beginner’s Guide to
Object-Oriented Programming
Have you started to learn to code, if your answer is yes then the most puzzling
question for you probably will be what exactly Object-Oriented
Programming is also known as, OOP?
It’s no denying fact that the technology industry has a fascination for terms.
Every now and then you will find a new term (for example 3D Touch and AR)
being trending and everybody is adding their thoughts about it- whether they
know it or not.
Now, because you are here I can safely assume that you must have heard or
was taught that object oriented programming is a better way to code but
without knowing the term itself in detail could land you into serious problems
later on.
Let’s begin our guide without wasting a single second now! !
Although it’s recommended to stick with the web version, if you want a pdf
copy of this click here.
What will you learn?
Before beginning to read any guide or tutorial you must know what you will
have learned after you have finished reading.
As the title suggests the article will be teaching you in’s and out of object
oriented programming. This guide will be the only thing you need to
understand OOP. Because everyone will be of different programming
backgrounds I will explain every concept with examples in real life and you
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 2 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
will never stumble ever again!
It doesn’t matter what level of coder you are appropriate knowledge of these
terms will help you a lot in the long run.
If you want you can bookmark this article for future reference.
Recommendation
If you are really interested in making your career as a programmer you must
go through this book: The Object-Oriented Thought Process(US visitors) |The
Object-Oriented Thought Process (Indian visitors) | The Object-Oriented
Thou
Process (for non-US/ non-Indian visitors)
Introduction
(You must read this whole, to understand why OOP was invented and to
also know some basic programming rules)
In the very beginning of their inventions, computers were programmed in
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 3 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
binary language i.e., 0’s and 1’s. With the advent of cheaper and larger storage
devices programming languages began to take shape and instead of now
instructing the computer in bits, coders could write their code in English.
These programming languages were relatively easy to code in but as capacity
and capabilities of computers continued to evolve the need for more complex
programs began. It was this stage that the languages started showing
limitations:
There was no way a piece of code could be reused. If you had to insert
same things in a program, you had to switch to duplication.
The control of program was transferred via goto statement. This was
very dangerous as several goto statements in the program made
understanding the flow of program incredibly problematic.
All variables (if you don’t know a variable is, remember it is actually a
named memory location) in the program were global. Meaning, once a
variable has been defined any function will have access to it.
To overcome these difficulties structures programming languages were
invented.
According to Wikipedia, the first structured programming language appeared
in early 1970’s. Structured programming language introduced Functions.
Large programs could now be divided into smaller units called function thus
making coding overall a simpler job. Functions solved three major problems
of the basic programming languages.
Reusability – With the invention of functions, whenever a part of the
code was required again the function would be ‘called’ and thus avoiding
duplication.
Global Variables – Each function could have its own variable (that
would be called local variable) and the scope (part of a program where a
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 4 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
variable is accessible) would be the within the function only.
Eradication of goto – New control instructions were defined that
eliminated the need to use goto statements
It’s very important to understand how these functions worked. There would
be several functions in the program so for the computer it will be difficult as
to what function should it execute first and thus came the ‘main’ function. In
any case, (whether there are other functions or not) the main function is
mandatory. The main function will be the only function that executes and all
other functions would from the main function in accordance with their order.
By separating different processes in different functions, It becomes easier to
maintain and develop complex programs.
This type of programming paradigm dominated for more than two decades
from1970’s to 1990’s. As the evolution of something is continuous, demand
for richer programs began and complexity began to show up in structured
programming language.
The limitations offered by structured programming languages can be enlisted
as:
Solving a problem was so unlike as you would do in real life and does
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 5 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
require a greater degree of mental effort.
Maintenance of huge programs was still very difficult.
A contrivance to reuse a piece of code was still not perfect.
That’s when Object Oriented Programming language began to take shape
Object-Oriented Programming language
OOP focuses on real life. How do to solve a problem in real life? We focus on
the object and the characteristics it possesses defines the procedure as to how
would we solve the problem. Let’s take an example.
How do you make a cup of coffee? First, you would think about the object
(here coffee) and its behavior. Then you would select tools (coffee machine)
and finally proceed with procedures. This is how you solve a problem in real
life.
Everything is object oriented. The programmers are also real people and
hence if the approach to solving problem also relates to the real world, solving
of a program would be a much easier task.
The most fundamental difference between these two fundamental paradigms
namely OOP and structure oriented programming is the design they are
developed upon. OOP programs focuses more on objects whereas Structured
programs focuses on process. What OOP basically does is that it ties data and
functions (procedures in real life) into a single unit.
Now that we know what OOP actually is, how do we define it?
According to Margaret Rouse from Tech Target,”Object Oriented
Programming is a programming language model organized around objects
rather than actions and data rather than logic.”
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 6 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
One of the essential features of OOP is data abstraction. Let’s take an
example. How do you drive a car? You will rotate the steering wheel and
change gears accordingly. Do you need to know how is fuel inside the engine
making the wheels move? Do you need to know how is the rotatory motion of
steering wheels propels the cars? The answer is no. OOP does exactly that. So,
when an end user uses a calculator app he or she needn’t know how is the
code implemented in PC.
Verdict and limitations of OOP
So, what did you learn?
Remember this when you solve problems (real life or while coding) rather
than thinking on how to divide the problem into functions try to divide it in
terms of objects – this will drastically improve productivity and this was the
whole idea behind OOP.
Nothing is perfect. OOP also comes with its own set of limitations. Sumita
Arora clearly marks them out as:
Designing of OOP programs is very tricky.
You need to have a proper plan before beginning to code.
The programmer needs to think in terms of object and apply brains to
correlate.
OOP has its own vocabulary that you will need to understand to continue to
code. First, let us enlist them and later we will try to explain them.
They are:
Objects
Classes
Inheritance
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 7 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
Polymorphism
Containership
Reusability
Tada! First, let’s target objects!
Objects
As discussed earlier, OOP divides the programs in terms of objects rather
than in procedures thus making manipulation easy. Basically, an object is
anything that has unique characteristics and nature. For example Mac Book
Pro or Taylor Swift.
Classes
It’s said that an object is an instance of a class. A class is a collection of
objects that share similar characteristics. For example, both Surface book and
Mack book Pro are objects as both have unique characteristics but there is a
class classed ”Laptop” in which both belongs as both share some common
characteristics.
Inheritance
OOP was built in such a way as to render greater reusability options.
Inheritance allows you to make another class by inheriting (like children
inherit from parents) other class (called the parent or base class). Examples
are the best way to understand things.
Let us take a class called Samsung Galaxy. We would want to create two other
classes Samsung Galaxy S7 and Samsung Galaxy S5. Both of these classes
would inherit from class Samsung Galaxy and in addition to it they will also
possess some unique features. Like both phones would run on Android and
possess a decent camera, but in additional to properties from class Samsung
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 8 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
Galaxy, they will also have unique
properties like Galaxy S7 will have a
low light optimized camera and Galaxy
S5 will have a eye scroller – notice
these two properties are what S7 and
S5 do not have in common. Samsung
Galaxy would be called the base
(parent) class whereas Galaxy S7 and
Galaxy S5 would be called derived(child) class.
OOP’s inheritance works in similar fashion.
Polymorphism
By definition, it is the ability to take more than one form. Did you understand
it? Let’s extend our example. Both of these phones would be put in Amazon’s
Samsung section so, how do we locate them? We would use filters and select
the year in which they were released in. We would easily find S7 in 2016 and
S5 in 2014.
Did you notice what did we do here? We used a common filter (function in
case of programs) and by the use of that we got different results. (Same filter
upon different conditions produce different results, thus the filter could be
said to be exhibiting polymorphism. )
Containership
I will start away with a real world example. In a typical online market like
Amazon you would find different items divided into categories like Clothing
and books and in each category Clothing are various sub-categories called
Men’s shirts or Women’s shoes. Men’s shirts and women shoes can be said to
be contained in Clothing. This is called containership. You will get to know
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 9 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
more of this as you move along with more advanced codes.
Reusability
Reusability is a core feature of OOP. Once a program is developed and tested
it would be distributed to various developers. OOP programs are designed in
such a way to facilitate easy sharing rendering faster and better apps.
Proper approach to code
Because coding Object-oriented programs are a mammoth task. The
programs are tricky therefore it’s very important that we make a proper plan.
Follow these:
1. Identify the supreme actors – important players.
2. Seek for the relation that exists between them (actors).
3. Recognize actions carried out by players.
Let us take an example.
(Originally example by Yahavant Kanetkar in his book Let Us C++)
Consider a college. The college will have more than one department with each
department offering one or more than one program, like a degree for B. Sc.
For every single program there will be several courses. Students will take
admission for a particular course and each course will be taught by a
professor who can teach multiple courses.
Can you now identify the actors? The easiest one to pick out is that a student
is an actor. (Find other actors on your own ! and comment down)
Now it’s time to seek for the relation between actors by looking at their
actions.
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 10 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
Students purchase form to take admission in a particular program. Students
will submit application form and fees. The college will examine application
forms and would either approve or reject candidature. Once approved, the
respective department will admit the student and would prepare a time table
for each program offered.
Professors would conduct classes according to the timetable and the
department will prepare an examination schedule would further conduct an
examination as per the schedule. Professors would evaluate answer sheets
and accordingly allots grades. Department will collect the grades and then
announce the result.
So, what exactly did we do? We focused on objects (actors – student,
department, etc.) then let their characteristics define the method to solve our
problem (here, college administration). This example clearly indicates how
OOP is related to real world.
Post Script
“Practice makes a man perfect”
11/13/17, 4(15 PMAbsolute Beginner's guide to Object-Oriented Programming
Page 11 of 11https://www.crayonpaper.com/object-oriented-programming-beginner/
Object-Oriented Programming
I hope that your confusions regarding object-oriented programming must
have been cleared. If you have any doubts of any kind do not forget to
comment down below. Also, do not forget to share this in your favorite sites
and subscribe to our newsletter for regular updates.
Sources and Citations:
Object-oriented programming – Wikipedia
Lesson: Object-Oriented Programming Concepts
Quora

Navigation menu