Why do we need virtual functions in C

Question

I'm learning C++ and am just starting to understand about virtual functions.

Virtual functions, according to what I've read (both in the book and online), are base class functions that can be overridden in derived classes.

However, I was able to override base functions in derived classes without using virtual earlier in the book when learning about fundamental inheritance.

So, what exactly am I missing? I know there's more to virtual functions than meets the eye, and it appears to be significant, so I'd like to be clear on what it is. I just can't seem to find a straight answer on the internet.

Answer 1

A virtual function is a base class member function that we expect to redefine in derived classes.

In the base class, a virtual function is used to ensure that the function is overridden. 

This is especially true when a pointer from a base class points to an object from a derived class.

For example, consider the code below:

class Base {
   public:
    void print() {
        // code
    }
};

class Derived : public Base {
   public:
    void print() {
        // code
    }
};