Access Specifiers in C++

Access specifiers in C++ define the scope and visibility of class members (variables and functions). They determine how members of a class can be accessed from other parts of the program. C++ provides three main access specifiers:

1. Public

Members declared as public are accessible from anywhere in the program.

Example:

    #include <iostream>

    class Car {
    public:
        std::string brand;

        void display() {
            std::cout << "Brand: " << brand << std::endl;
        }
    };

    int main() {
        Car car1;
        car1.brand = "Toyota";  // Accessible directly
        car1.display();         // Accessible directly

        return 0;
    }
        

Output:

    Brand: Toyota
        

2. Private

Members declared as private are accessible only within the class. They cannot be accessed directly from outside the class.

Example:

    #include <iostream>

    class Car {
    private:
        std::string brand;

    public:
        void setBrand(const std::string &b) {
            brand = b;  // Setting private member
        }

        void display() {
            std::cout << "Brand: " << brand << std::endl;  // Accessing private member
        }
    };

    int main() {
        Car car1;
        car1.setBrand("Honda");  // Indirectly setting private member
        car1.display();

        return 0;
    }
        

Output:

    Brand: Honda
        

3. Protected

Members declared as protected are accessible within the class and its derived (child) classes but not from outside these classes.

Example:

    #include <iostream>

    class Vehicle {
    protected:
        int speed;

    public:
        void setSpeed(int s) {
            speed = s;
        }
    };

    class Car : public Vehicle {
    public:
        void displaySpeed() {
            std::cout << "Speed: " << speed << " km/h" << std::endl;  // Accessing protected member
        }
    };

    int main() {
        Car car1;
        car1.setSpeed(120);  // Accessing public method of parent class
        car1.displaySpeed();

        return 0;
    }
        

Output:

    Speed: 120 km/h
        

Comparison of Access Specifiers

Access specifiers in C++ provide control over data hiding and ensure encapsulation, allowing developers to safeguard and organize their code effectively.