A function can be [overridden](https://www.educative.io/answers/overloading-vs-overriding) using inheritance to change its behavior. However, sometimes, we don't need to completely alter or replace the functionality of the base (parent) class; instead, we need to *add* more functionality. In order to do this, the derived (child) class can call the parent's function first (using the scope resolution operator `::`) and then implement the additional functionality.

>Re-using the parent's code lets us write less code in the derived class.

#include <iostream>
using namespace std;

class Base{
  public:
    void foo(){
      cout << "Base class functionality" << endl;
    }
};

class Derived: public Base{
  public:
    // Overriding foo():
    void foo(){
      Base::foo(); // Calling foo() of Base class
      cout << "Derived class functionality" << endl;
    }
};

int main() {
  Derived d;
  d.foo();

  return 0;
}

How to call an overridden function in C++

Re-use the base class's code in derived class by calling the parent's function using ::.

How to call an overridden function in C++

Code