How Do I Call a Base Class's Virtual Function in C After Overriding It?

Calling a Base Class's Virtual Function in C After Overriding

In software development, it's common to encounter scenarios where you need to call a base class's function from a derived class, even if you've overridden that function. In C , unlike Java, you cannot use a simple super.funcname() syntax to achieve this.

Consider the following code snippet:

class Foo {
public:
    int x;

    virtual void printStuff() {
        std::cout << x << std::endl;
    }
};

class Bar : public Foo {
public:
    int y;

    void printStuff() {
        // I would like to call Foo.printStuff() here...
        std::cout << y << std::endl;
    }
};

In this example, Bar inherits from Foo and overrides the printStuff() function. However, you may want to retain the original functionality of Foo::printStuff() in certain contexts.

To call the base class's printStuff() function in C , you must explicitly name the base class using the :: operator. Here's how:

class Bar : public Foo {
  // ...

  void printStuff() override {  // help the compiler to check
    Foo::printStuff(); // calls base class' function
  }
};

In this modified code, the Foo::printStuff() base class function is called within the overridden Bar::printStuff() function. The override keyword helps the compiler verify that the function is indeed overriding a base class function.

By explicitly calling the base class function, you gain the flexibility to use both the base and derived class implementations of printStuff(). This can be useful in various scenarios, such as calling the original function to perform common tasks before or after the overridden implementation.

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