C++ Encapsulation

Encapsulation is a way of organizing data members (attributes) and function members (methods) by wrapping them together in a single class. By bundling them together in a single unit, the code is cleaner, more readable, and more maintainable.

class Example {
  // Some attributes
  // Some methods
}

Here’s a Rectangle class with length and width attributes and a .Area() method:

class Rectangle {
  public:
    int length;
    int width;

  int Area() {
    return length * width;
  }
};

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Data Hiding

Encapsulation led to the important OOP concept of data hiding or abstraction.

Access specifiers are C++ keywords that determine the scope of class components:

• public: Public class members are accessible from anywhere in the program.
• private: Private class members are only accessible from inside the class.

Data hiding is achieved by declaring class attributes as private:

#include <iostream>

class Encapsulation {
  private:
    // Data hidden from outside world
    int num;

  public:
    // Function to set value of num
    void setNum(int x) {
      num = x;
    }

    // Function to return value of num
    int getNum() {
      return num;
    }
};

int main() {
  Encapsulation obj;

  obj.setNum(10);

  std::cout << obj.getNum() << "\n"; // Output: 10

  return 0;
}

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In the example above, the num attribute and .setNum() and .getNum() methods are wrapped together into one class called Encapsulation.

• num can only be accessed by either the .setNum() or .getNum() method.
• .setNum() is used to set the value of num.
• .getNum() is used to return the value of num.