Visibility Modes in C++: Public, Private, Protected

In C++, visibility modes control the accessibility of class members (data members and member functions) from other classes. This is crucial for encapsulation and information hiding. C++ provides three visibility modes:

1. Public:

• Public members are accessible from anywhere, including within the class, derived classes, and other classes.

• They are often used for data members that need to be accessed and modified by other parts of the program.

Example:

#include <iostream>

using namespace std;

class PublicClass {
public:
    int public_var;
    void public_function() {
        cout << "Public function" << endl;
    }
};

int main() {
    PublicClass obj;
    obj.public_var = 10;
    obj.public_function();
    return 0;
}

2. Private:

• Private members are only accessible within the class itself.

• They are used to hide implementation details and protect data integrity.

Example:

#include <iostream>

using namespace std;

class PrivateClass {
private:
    int private_var;
public:
    void setPrivateVar(int value) {
        private_var = value;
    }
    int getPrivateVar() {
        return private_var;
    }
};

int main() {
    PrivateClass obj;
    obj.setPrivateVar(20);
    cout << obj.getPrivateVar() << endl;
    return 0;
}

3. Protected:

• Protected members are accessible within the class itself and its derived classes.

• They are often used to create base classes that provide a foundation for derived classes.

Example:

#include <iostream>

using namespace std;

class ProtectedClass {
protected:
    int protected_var;
public:
    void setProtectedVar(int value) {
        protected_var = value;
    }
};

class DerivedClass : public ProtectedClass {
public:
    void printProtectedVar() {
        cout << protected_var << endl;
    }
};

int main() {
    DerivedClass obj;
    obj.setProtectedVar(30);
    obj.printProtectedVar();
    return 0;
}

By understanding and effectively using these visibility modes, you can create well-structured, maintainable, and secure C++ programs. Remember to carefully consider the accessibility of your class members to ensure proper encapsulation and information hiding.