Quiz 12: Inheritance

Which access modifier in C++ allows the derived class to access the public members of the base class?

• public

• protected

• private

• friend

What is the output of the following C++ code?

#include <iostream>

using namespace std;

class Base {

public:

int publicVar = 5;

protected:

int protectedVar = 10;

private:

int privateVar = 15;

};

class Derived : public Base {

public:

void display() {

cout << "Public Variable: " << publicVar << endl;

cout << "Protected Variable: " << protectedVar << endl;

cout << "Private Variable: " << privateVar << endl;

}

};

int main() {

Derived obj;

obj.display();

return 0;

}

• Compilation Error

• Public Variable: 5, Protected Variable: 10, Private Variable: 15

• Public Variable: 5, Protected Variable: 10

• Private Variable: 15

Answer explanation

The output of the code will be "Public Variable: 5, Protected Variable: 10". Since the derived class is inheriting publicly from the base class, it can access the public members of the base class. However, it cannot access the private members of the base class.

Which access modifier in C++ allows only the base class to access its members?

• private

• public

• protected

• friend

What is the output of the following C++ code?

#include <iostream>

using namespace std;

class Base {

public:

int publicVar = 5;

protected:

int protectedVar = 10;

private:

int privateVar = 15;

};

class Derived : private Base {

public:

void display() {

cout << "Public Variable: " << publicVar << endl;

cout << "Protected Variable: " << protectedVar << endl;

cout << "Private Variable: " << privateVar << endl;

}

};

int main() {

Derived obj;

obj.display();

return 0;

}

• Compilation Error

• Public Variable: 5, Protected Variable: 10, Private Variable: 15

• Public Variable: 5, Protected Variable: 10

• Private Variable: 15

Answer explanation

The code will not compile because the derived class is inheriting privately from the base class, which means that the public and protected members of the base class will become private members of the derived class. As a result, the derived class cannot access the public and protected members of the base class using the dot operator.

What is the output of the following C++ code?

#include <iostream>

using namespace std;

class Base

{

public: int publicVar = 5;

protected: int protectedVar = 10;

private: int privateVar = 15;

};

class Derived : Base

{

public:

void display() {

cout << "Public Variable: " << publicVar << endl;

cout << "Protected Variable: " << protectedVar << endl;

cout << "Private Variable: " << privateVar << endl; }

};

int main()

{ Derived obj;

obj.display();

return 0; }

• Compilation Error

• Public Variable: 5, Protected Variable: 10, Private Variable: 15

• Public Variable: 5, Protected Variable: 10

• Private Variable: 15

Which access modifier in C++ allows a function in the base class to access the private members of the derived class?

• public

• protected

• private

• friend

What is the output of the following C++ code?

#include <iostream>

using namespace std;

class Base {

public:

void display(Derived obj) {

cout << "Public Variable: " << obj.publicVar << endl;

cout << "Protected Variable: " << obj.protectedVar << endl;

cout << "Private Variable: " << obj.privateVar << endl;

}

};

class Derived : public Base {

private:

int privateVar = 15;

public:

int publicVar = 5;

protected:

int protectedVar = 10;

friend void Base::display(Derived obj);

};

int main() {

Derived obj;

Base b;

b.display(obj);

return 0;

}

• Compilation Error

• Public Variable: 5, Protected Variable: 10, Private Variable: 15

• Public Variable: 5, Protected Variable: 10

• Private Variable: 15