Encapsulation in object-oriented programming involves wrapping data and functions that work on that data within a single unit called a class. This bundling of data and functions protects the data from outside modification and exposes a controlled interface. Encapsulation provides data hiding by restricting direct access to data members and requiring use of accessor functions, allowing control over modification and maintaining integrity. It improves maintainability, readability and security of code by combining related data and functions.

1. CS Lecturer: Bibi Maryam

2. Encapsulation

3. Encapsulation Def.
 The meaning of Encapsulation, is to make sure that "sensitive" data is
hidden from users. To achieve this, you must declare class
variables/attributes as private (cannot be accessed from outside the
class). If you want others to read or modify the value of a private
member, you can provide public get and set methods.

4. Encapsulation’s Important points :
 Encapsulation involves combining similar data and functions into a single
unit called a class.
 By encapsulating these functions and data, we protect that data from change.
 This concept is also known as wrapping data or information hiding.
 In Object Oriented Programming, Encapsulation is defined as binding together
the data and the functions that manipulate them.

6. Two Important properties of
Encapsulation:
1. Data Protection: Encapsulation protects the internal state of an object by
keeping its data members private. Access to and modification of these data
members is restricted to the class’s public methods, ensuring controlled and
secure data manipulation.
2. Information Hiding: Encapsulation hides the internal implementation details
of a class from external code. Only the public interface of the class is
accessible, providing abstraction and simplifying the usage of the class while
allowing the internal implementation to be modified without impacting
external code.

7. A real-life example of Encapsulation
1. In a company, there are different sections like the accounts section, finance
section, sales section, etc. Now,
2. The finance section handles all the financial transactions and keeps records of
all the data related to finance.
3. Similarly, the sales section handles all the sales-related activities and keeps
records of all the sales.
4. Now there may arise a situation when for some reason an official from the
finance section needs all the data about sales in a particular month.
5. In this case, he is not allowed to directly access the data of the sales section.
He will first have to contact some other officer in the sales section and then
request him to give the particular data.

8. Features of Encapsulation:
 Below are the features of encapsulation:
a. We can not access any function from the class directly. We need an object to
access that function that is using the member variables of that class.
b. The function which we are making inside the class must use only member
variables, only then it is called encapsulation.
c. If we don’t make a function inside the class which is using the member
variable of the class then we can’t call it encapsulation.
d. Encapsulation improves readability, maintainability, and security by grouping
data and methods together.
e. It helps to control the modification of our data members.

9. Example:
#include <iostream>
using namespace std;
// declaring class
class Circle {
// access modifier
private:
// Data Member
float area;
float radius;
public:
void getRadius()
{
cout << "Enter radiusn";
cin >> radius;
}
void findArea()
{
area = 3.14 * radius * radius;
cout << "Area of circle=" <<
area;
}
};
int main()
{
// creating instance(object) of class
Circle cir;
cir.getRadius(); // calling function
cir.findArea(); // calling function
}
Output: Enter radius
Area of circle=0

10. Role of Access Specifiers in Encapsulation:
 Access specifiers facilitate Data Hiding in C++ programs by
restricting access to the class member functions and data
members. There are three types of access specifiers in C++:
 Private: Private access specifier means that the member function
or data member can only be accessed by other member functions
of the same class.
 Protected: A protected access specifier means that the member
function or data member can be accessed by other member
functions of the same class or by derived classes.
 Public: Public access specifier means that the member function or
data member can be accessed by any code.
 By default, all data members and member functions of a class are
made private by the compiler.

11. Points to Consider:
 As we have study, access specifiers play an important role in implementing
encapsulation in C++. The process of implementing encapsulation can be sub-
divided into two steps:
1) Creating a class to encapsulate all the data and methods into a single unit.
2) Hiding relevant data using access specifiers.

12. Getter & Setter methods:
 The getter function is used to retrieve the variable value and the setter
function is used to set the variable value. Remember: You can directly
access public member variables, but private member variables are not
accessible. Therefore, we need getter functions.

13. Access Private Members:
 To access a private attribute, use public "get" and "set" methods:
#include <iostream>
using namespace std;
class Employee {
private:
// Private attribute
int salary;
public:
// Setter
void setSalary(int s) {
salary = s;
}
// Getter
int getSalary() {
return salary;
}
};
int main() {
Employee myObj;
myObj.setSalary(50000);
cout << myObj.getSalary();
return 0;
}

14. Why Encapsulation?
 It is considered good practice to declare your class attributes
as private (as often as you can). Encapsulation ensures better
control of your data, because you (or others) can change one
part of the code without affecting other parts.
 Increased security of data.