Real Life Example Of OOPS

Introduction

We are going to see here some real life examples of Object Oriented Programming (OOPS).

The following are the principles of OOPS:

1. Class
2. Object
3. Constructor (Note: This is not actual principal)
4. Abstraction
5. Encapsulation
6. Polymorphism
7. Inheritance
8. Destructor (Note: This is not actual principal)

Description

Before proceeding further let’s look into background.Before OOPS concept came into picture (market) there was "C Language" designed & developed by Dennis Ritchie in 1972 at AT & T Laboratory.

C language is a general purpose, block structured, case sensitive & procedure oriented language.
Program execution always goes from top to bottom.

Let’s see how a C program gets compiled & run.

CLR like the following figure:



Example

This example is divided into two parts; firstly, Procedure Oriented approach and secondly Object oriented approach.

There is one poor family in Maharashtra. They have their own business to pick up fish from sea & sell that in the local market. In that family there were members including husband, wife & children. Everyday they do the same thing for their business. After some years they did not earned a good amount of profit from their business because daily expenses were bigger than what they earned from the business.

So husband & wife decided to do some other business. So they visited on of their relatives and ask for some suggestions. They got a suggestion to make Ganesh statues to sell them. This was suggested because it is one of the best business since Ganesh Chaturthi is an important festival and celebrated across Indian homes.

• They take Shaadu (Fire Clay / dry mud powder), water, knot, color, brush, etc.
  
  
  
  
• First they take Shaadu in a vessel and start mixing water. Keep in mind the mixture can get very thick making your fingers ache as you try to take off the clay sticking on them.
  
  
  
  
• After this mixture is ready, give them a shape of Ganesh statue.
  
  
  
  
• Start off with creating a base structure of the idol / Ganesh statue:
  
  
  
  
• Leave the idol / statue to dry naturally for 2 days at least, after 2 days if statue is completely dry then start giving color to them.
  
  

For doing the above procedure they need extra time & days because firstly they have to give it a proper shape, statue should need to dry completely, after that give proper color to this statue. If sometimes statue gets cracked or shape didn't came out well, then they have do repeat the whole procedure from first to last. So it is very time consuming.

In this procedure suppose for completing 1 Ganesh statue it takes 5 days i.e approximately each month they completed 6 Ganesh statue (every year 72).

For first year they sold 72 statues. After this 72 statue reached in 72 homes, relatives & neighbours loved the statue. So for next year this family got an advance order of 2000 Ganesh statue which are in different shapes like 1 feet, 2 feet, 5 feet, 10 feet & 20 feet.

The family member again visited their relative to resolve these relevant questions i.e How can they complete 2000 Ganesh statues in one year? So they gave suggestion to use mold (meaning - a hollow container used to give shape to molten or hot liquid material when it cools and hardens) to give proper shapes to Ganesh statues.

Now the family used these different molds like 1 feet, 2 feet, 5 feet, 10 feet & 20 feet. Following this, they can complete 100 Ganesh statue per day.

Here they followed the procedure which is Object Oriented Programming Approach.

• Firstly, they took Shaadu in a vessel and started mixing water, after they took knot, mixed it in that pot & added this knot to mold.
  
  

This mold is like a predefined class.

Class

• Class is a blue print of newly created things.
  
  
• Class contains characteristics (class members) and behaviors (function applied on these characteristics).
  
  
• It is a blue print such as if we bought a land / space & would like to build a beautiful house on that land then we first draw a sketch.
  
  
• In our programming language before going to create any application first we decide which classes we are going to create.
  
  1. class Ganesh_Statue {
  2. // class members declerations
  3. public string shaadu;
  4. public string knot;
  5. public string water, pot;
  6. public string One_Tusk, Big_Head;
  7. public string chain, ring;
  8. public string mouse_color, Eye_Color, Skin_Color;
  9. public void Do_Painting() {}
  10. }

Object

• Objects are instances of class.
  
  
• Whenever they create first Ganesh statue from this mold, it creates first object & it will look like the following:
  
  
  
  
• Whenever they create multiple Ganesh statues (multiple objects) by using mold and added other parts like hand, legs etc, it looks like the following:
  
  

Abstraction

• Abstraction means hiding the implementation details.
  
  
• This family only knows which type of material they have used to create a statue.
  
  
• This family uses knot, shaadu, water, etc to make the statue and this information is hidden from the users (who can buy this Ganesh statues).
  
  If we ask anybody that what we can understand from the above image, then he / she will say that these are all stones.

Constructor

• Constructor is a method that is called when instance of an object is created.
  
  
• They have the same name as a class.
  
  
• In our example default constructor is to be set with values such as eye color, skin color and mouse color.
  
  
• After calling the default constructor Ganesh statue will look like the following:
  
  
  
  1. //constructor
  2. public Ganesh_Statue() {
  3. Console.WriteLine("**** Dafult Constructor in base class starts from here ****");
  4. Eye_Color = "Black";
  5. Skin_Color = "Redish_White";
  6. mouse_color = "Black";
  7. Console.WriteLine("Default values of Eye color: " + Eye_Color);
  8. Console.WriteLine("Default values of skin color: " + Skin_Color);
  9. Console.WriteLine("Default values of mouse colo: " + mouse_color);
  10. Console.WriteLine("____________________________________________________________________________");
  11. Console.WriteLine();
  12. }
  A. Parameterized Constructor
  
  
  1. A constructor with at least one parameter is called parameterized constructor.
     
     
  2. In our example suppose a wealthy businessman came to this family & gave some parameter like he wants to add his own jewellery to statue like chain & ring.
     
     1. // parameterized constructor
     2. public Ganesh_Statue(string x, string y) {
     3. chain = x;
     4. ring = y;
     5. Console.WriteLine("____________________________________________________________________________");
     6. Console.WriteLine("**** Parameterized Constructor of base class starts from here ****");
     7. Console.WriteLine("chain color: " + x + " ring color: " + y);
     8. Console.WriteLine("____________________________________________________________________________");
     9. Console.WriteLine();
     10. }

Encapsulation

• Encapsulation means biding data & function together.
  
  
• For example, we visit the Doctor or Medical store and take medicine(capsule / tablet), then the plastic cover is used to bind with inner powder which helps us to recover.

Polymorphism

Now this family has to decide about some people who have domain specific knowledge like painting.