The main difference between a pure virtual function and a virtual function is: The member access specifier. That a pure virtual function cannot have an implementation. The return type. The location in the class.

A pure virtual function is like a promise in C++—it declares that a class will provide an implementation in a derived class, but it doesn't have any definition in the base class itself, making the base class an abstract class. This means you cannot instantiate it directly. On the other hand, a virtual function is more like a suggestion; it may have an implementation in the base class that can be overridden by derived classes. Understanding how to properly use these functions can save you from common pitfalls. A frequent mistake is trying to instantiate a class with pure virtual functions, which results in a compilation error. Another issue is forgetting to override the pure virtual function in the derived class, leading to another compilation error when the derived class is instantiated. Always double-check that your derived classes fulfill the promises made by their base classes!