Object oriented Programming concepts in C++ with example

 

An introduction of Object-oriented Programming concepts in C++ with example

Fundamental terms and basic idea

Everything in oops is associate with class and object. The class also have an attribute (Variable) and methods (Function). An object is known as a model of some real or imaginary world. For example, your laptop is an object. The laptop has attributes, such as color, weight, ram, and method, such as shutdown.

Example

Object	Properties	abilities
Ram	Hair color:black  height:180 cm	Walk,speak,see,hear
Shyam	Hair color: green height:140	Walk,speak,see,hear
Laptop	Company :Dell	Power on,boot,crash
Pendrive	Capacity:16 GB	Read, write

 

Class: Group of object with similar properties and common behavior.

A class is a user-defined data type the same as int or float. The class used in our program as a data type. We   can also say it’s a blueprint to creating object.

Example

Class	Properties	abilities
Person	Name:string,hair colour:string, height:integer	Walk,speak,see,hear
Computer	Type:string, capacity:integer	Power on,boot,crash

 

The properties of class is called attributes and abilities are called method.

Data encapsulation

Normally the internal arrangement of the class should not be visible form the external class. To access restricted attribute of an internal class public keyword is used. There are private and protected are also used in class.

Inheritance

Assume you create a class of Ram. This class has attributes like Hair color and height and method walk, speak. If you have to take another class shayam .Shayam class also have the same attribute and method, If you use inheritance you can inherit rams attribute and method directly without writing.

Polymorphism

A call of the method may invoke different codes.Function with same name but different data type or passing value.

 

Class Diagram

Call diagram is consist of class name, attributes and methods and their operations.

Access Specifier in C++

·       + : public (No access restriction) the attribute can access form outside class

·       -: private (Access only inside the class) attribute or method who is private can only access within the class. That is a reason public function is using to set value in the attribute.

·       #: Protected (Very useful in inheritance)Access where object is visible.

Note 

By default, all members declared with in-class has private access specifiers in C++.

Inheritance

This is most useful concept in OOPs, this allows building hierarchy of classes. Exam ram and shayam are specializations are human, We can say human is the superclass of ram. Ram is a subclass of human.

A subclass inherits all attributes and operation of their superclass. We are free to add some extra attributes and methods in the subclass. To subclass have their own attribute and method as well as Superclass attributes and methods.

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