Cpp Programming Practice Exam

The four pillars of OOP are:

• Encapsulation – bundling data and methods together
• Abstraction – hiding complex implementation details
• Inheritance – deriving new classes from existing ones
• Polymorphism – using a single interface for different types

A class is a user-defined type that encapsulates data members and member functions. Defined with the class keyword:
class MyClass { public: int x; void show(); };

The only default difference is access control:

• class members are private by default
• struct members are public by default

Inheritance allows a derived class to inherit members from a base class:
class Dog : public Animal { };
This promotes code reuse and establishes an is-a relationship.

A virtual function is declared with the virtual keyword in a base class, enabling runtime polymorphism:
virtual void speak() { }
Derived classes can override it, and the correct version is called via a base class pointer using the vtable.