ऑब्जेक्ट-ओरिएंटेड प्रोग्रामिंग (OOP) में एब्सट्रैक्ट क्लास (Abstract Class) क्या है?

Which of the following statements is/are FALSE? (i) Key features of object-oriented programming include abstraction, encapsulation, polymorphism, and inheritance. (ii) Object-based languages support the usage of objects, but need not support inheritance or polymorphism or both.

In the following C++ code fragment, what is 'Demo()' called? class Demo { private: int a; int b; public: Demo(); void set(int a, int b); void print(); };