C++ and OOP MCQs for placement tests

Which OOP feature allows the same function name to behave differently for different argument types?

What is the output of this C++ program?

#include <iostream>
using namespace std;
class Base { public: Base() { cout << "Base "; } };
class Derived : public Base { public: Derived() { cout << "Derived "; } };
int main() { Derived d; return 0; }

What is the output of this C++ program?

#include <iostream>
using namespace std;
class Base { public: ~Base() { cout << "~Base "; } };
class Derived : public Base { public: ~Derived() { cout << "~Derived "; } };
int main() { { Derived d; } return 0; }

What is the output of this C++ program?

#include <iostream>
using namespace std;
class Base { public: virtual void show() { cout << "Base"; } };
class Derived : public Base { public: void show() override { cout << "Derived"; } };
int main() { Base *b = new Derived(); b->show(); return 0; }

What is the output of this C++ program?

#include <iostream>
using namespace std;
class Base { public: void show() { cout << "Base"; } };
class Derived : public Base { public: void show() { cout << "Derived"; } };
int main() { Base *b = new Derived(); b->show(); return 0; }

A class that contains at least one pure virtual function is called:

Which access specifier makes members accessible in the class and its derived classes, but not outside?

What is the default access specifier for members of a class in C++?

Which keyword lets a function access the private members of a class without being a member?

What is the output of this C++ program?

#include <iostream>
using namespace std;
int add(int a) { return a; }
int add(int a, int b) { return a + b; }
int main() { cout << add(5, 2); return 0; }

What is the output of this C++ program?

#include <iostream>
using namespace std;
int main() { int x = 10; int &r = x; r += 5; cout << x; return 0; }

Wrapping data and the functions that work on it into a single unit is called:

Which type of inheritance can cause the 'diamond problem'?

Which operator cannot be overloaded in C++?

What is a copy constructor used for?

What is the output of this C++ program?

#include <iostream>
using namespace std;
class A { public: static int count; A() { count++; } };
int A::count = 0;
int main() { A a, b; cout << A::count; return 0; }

Which of these is used for dynamic memory allocation in C++?

What does the 'this' pointer point to?

In C++, which container provides fast lookup by key with keys kept in sorted order?

What is the output of this C++ program?

#include <iostream>
#include <vector>
using namespace std;
int main() { vector<int> v = {4, 5, 6}; cout << v.size(); return 0; }