Inheritance
When declaring a class in C++, we have the ability to inherit from another class. In fact, we can inherit from multiple classes at the same time—a feature of C++ that not all object-oriented languages share. When we inherit from another class, we gain all its members that have either public or protected privacy modifiers. Private members remain visible only to the class in which they're defined, not the inheriting class. This is one of the fundamental concepts in OOP and allows us to build flexible, maintainable objects where common functionality can be declared only once, then implemented and extended where needed.
Let's use vehicles and look at a quick example. We might define a base class, Vehicle, that defines some common properties, such as the maximum speed or the number of doors. We could then inherit from this class to create specialized vehicle classes such as Car, Bike, or Lorry. We create multiple classes that share a common base class and...