Access modifiers

Access Modifiers

Access modifiers in C++ are keywords used to set the access level of class members (variables and functions). They control who can access the members of a class from outside or inside the class.

There are three main access modifiers in C++:

1. Public

• Members declared as public are accessible from anywhere in the program where the object is visible.
• These are often used for functions that need to be called from outside the class.

class Student {
public:
    int rollNo;           // Can be accessed directly
    void display() {
        cout << rollNo;
    }
};

2. Private

• Members declared as private are accessible only inside the class.
• They cannot be accessed directly from outside the class.
• This is used for data protection (encapsulation).

class Student {
private:
    int marks;           // Cannot be accessed from outside
public:
    void setMarks(int m) {
        marks = m;
    }
    int getMarks() {
        return marks;
    }
};

In this example, marks can only be accessed using setMarks() and getMarks().

3. Protected

• Members declared as protected are like private, but they can also be accessed in derived (child) classes.
• Commonly used in inheritance.

class Person {
protected:
    string name;
};

class Student : public Person {
public:
    void setName(string n) {
        name = n;      // Allowed because name is protected
    }
};

Summary Table:

Why Access Modifiers Are Important:

• Help protect data from unauthorized access or modification
• Allow abstraction and encapsulation
• Control how other parts of the program interact with a class

Using access modifiers properly makes the code more secure, organized, and easier to manage.