THINK++ — Engineering Visualized

Runtime Polymorphism

Function Overriding

Occurs when a derived class provides a specific implementation for a function that is already defined in its base class.

THE OVERRIDE

class Parent {
public:
    virtual void show() { cout << "Parent"; }
};

class Child : public Parent {
public:
    void show() override { cout << "Child"; } // Override
};

VIRTUAL KEYWORD

The base class function MUST be marked virtual to enable overriding.

OVERRIDE SPECIFIER

Using override (C++11) is optional but helps the compiler catch errors.

RECALLING BASE METHOD

Inside the overridden function, you can still call the base class version using the scope resolution operator: Parent::show();

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