A virtual function is a member function which is declared within a base class and is re-defined(Overridden) by a derived class. When you refer to a derived class object using a pointer or a reference to the base class, you can call a virtual function for that object and execute the derived class’s version of the function.

A pure virtual function (or abstract function) in C++ is a virtual function for which we don’t have an implementation, we only declare it. A pure virtual function is declared by assigning 0 in the declaration.

Similarities between virtual function and pure virtual function

1. These are the concepts of Run-time polymorphism.
2. Prototype i.e. Declaration of both the functions remains the same throughout the program.
3. These functions can’t be global or static.

Difference between virtual function and pure virtual function in C++

virtual<func_type><func_name>()
{
    // code
}

virtual<func_type><func_name>()
    = 0;