Encapsulation - EduardoMSU/OOP-2143 GitHub Wiki

Encapsulation in Object-Oriented Programming

What Is Encapsulation?

Encapsulation is a fundamental principle of object-oriented programming (OOP) that involves bundling data (attributes) and methods (functions) that operate on the data into a single unit, i.e., a class. Encapsulation restricts direct access to an object’s internal state and enforces access control through defined interfaces.

Key Characteristics of Encapsulation

Characteristic Description
Data Hiding Internal details of the class are hidden from the outside world using access modifiers.
Controlled Access Public methods provide controlled access to private attributes.
Improved Security Prevents unauthorized or accidental modification of data.
Modularity Promotes modular design by separating the implementation from the interface.
Ease of Maintenance Changes in the internal workings of a class don’t affect code that interacts with it externally.

Access Modifiers in C++

Encapsulation is enforced in C++ using access modifiers:

Access Modifier Description
private Members are accessible only within the same class.
protected Members are accessible within the same class and derived classes.
public Members are accessible from outside the class.

Example of Encapsulation in C++

Below is an example demonstrating encapsulation in C++:

Example:

#include <iostream>
#include <string>

class Employee {
private:
    std::string name;  // Private attribute
    int age;           // Private attribute

public:
    // Constructor
    Employee(const std::string& empName, int empAge) : name(empName), age(empAge) {}

    // Getter for name
    std::string getName() const {
        return name;
    }

    // Setter for name
    void setName(const std::string& newName) {
        name = newName;
    }

    // Getter for age
    int getAge() const {
        return age;
    }

    // Setter for age
    void setAge(int newAge) {
        if (newAge > 0) {  // Validation
            age = newAge;
        } else {
            std::cout << "Age must be positive!" << std::endl;
        }
    }

    // Method to display employee details
    void displayDetails() const {
        std::cout << "Name: " << name << ", Age: " << age << std::endl;
    }
};

int main() {
    Employee emp("Alice", 25);

    // Access and modify private members using public methods
    emp.displayDetails();
    emp.setName("Bob");
    emp.setAge(30);
    emp.displayDetails();

    // Attempt to set invalid age
    emp.setAge(-5);

    return 0;
}
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