A.3: Encapsulation

Encapsulation

Encapsulation is defined as wrapping up of data and information under a single unit. In Object Oriented Programming, Encapsulation is defined as binding together the data and the functions that manipulates them.

Consider a real life example of encapsulation, in a company there are different sections like the accounts section, finance section, sales section etc. The finance section handles all the financial transactions and keep records of all the data related to finance. Similarly the sales section handles all the sales related activities and keep records of all the sales. Now there may arise a situation when for some reason an official from finance section needs all the data about sales in a particular month. In this case, he is not allowed to directly access the data of sales section. He will first have to contact some other officer in the sales section and then request him to give the particular data. This is what encapsulation is. Here the data of sales section and the employees that can manipulate them are wrapped under a single name “sales section”.

// c++ program to explain 
// Encapsulation 
  
#include<iostream> 
using namespace std; 
  
class Encapsulation 
{ 
    private: 
        // data hidden from outside world 
        int someNum; 
          
    public: 
        // function to set value of  
        // variable someNum 
        void set(int inputVal) 
        { 
            someNum = inputVal; 
        } 
          
        // function to return value of 
        // variable someNum
        int get() 
        { 
            return someNum; 
        } 
}; 
  
// main function 
int main() 
{ 
    Encapsulation myObj; 
      
    myObj.set(5); 
      
    cout << myObj.get() << endl; 
    return 0; 
} 

Output:

5

In the above program the variable someNum is made private. This variable can be accessed and manipulated only using the functions get() and set() which are present inside the class. Thus we can say that here, the variable x and the functions get() and set() are bound together which is nothing but encapsulation.

Role of access specifiers in encapsulation

As we have seen in above example, access specifiers plays an important role in implementing encapsulation in C++. The process of implementing encapsulation can be sub-divided into two steps:

1. The data members should be labeled as private using the private access specifiers
2. The member function which manipulates the data members should be labeled as public using the public access specifier

 Adapted from:
"Encapsulation in C++" by Harsh Agarwal, Geeks for Geeks is licensed under CC BY-SA 4.0