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1.3.2 Data Abstraction
The word abstract means existing in thought as an idea but does not have a tangible existence. Data Abstraction
is the property by which the essential features of a class are represented without informing about the background
details, i.e., non-essential details are hidden from the user.
For example, while travelling in a car as a passenger, you think only of
reaching the destination. But you never think of how the driver is
driving the car by pressing the clutch, brake and accelerator as and
when required. Similarly, in case of the driver, he is only concerned
about the steering wheel, accelerator, clutch and brake. But he is least
interested in how they execute their functions.
Similarly, the key purpose of abstraction in OOP is to hide the details that are not required by
the users. Abstraction is like a query passed to a database which extracts the required data
only leaving the rest. The main purpose is to reduce the programming complexity. It is one of
the most important concepts of OOPs.
Let us understand with another example, while using an Automated Teller Machine (ATM),
we only concentrate on executing the operations like cash withdrawal which includes
inserting the card, typing the PIN and amount of cash, etc. But we never think of how
exactly that operation is executed internally, so that we could get the service correctly.
Thus, it is a real-life example of abstraction as the detailed functioning of the ATM is hidden
from the user.
1.3.3 Difference between Abstraction and Encapsulation
Abstraction Encapsulation
Issues at the design level can be solved. Issues at the implementation level can be solved.
Abstraction is about hiding unwanted details and In encapsulation, the methods and data are kept
showing only the essential information. in a single unit.
Abstraction focuses on what the information object It hides the internal details of how an object does
must contain and present to the outside world. something for security reasons.
1.3.4 Inheritance
The procedure of generating a new class with the help of a class already created by using its properties and
functionality is said to be inheritance. It is one of the important pillars of Object-Oriented Programming.
For example, in real world, a child inherits the properties (both materialistic and non-materialistic) of its parents,
who, in turn, inherited them from their parents.
Principles of Object-Oriented Programming 19

