What role does destructor play in polymorphism in C++?

Destructors are crucial in C++ polymorphism, ensuring that derived class objects properly clean up memory when they are destroyed. Polymorphism allows objects of different types to respond to the same method call. The destructor is automatically called when an object is destroyed to release its memory. The derived class destructor calls the base class destructor to ensure that the base class memory is released.

The role of destructor in polymorphism in C++

The role of destructor in polymorphism in C++ It plays a vital role in ensuring that the memory of derived class objects is cleaned up in an appropriate manner when they are destroyed.

Introduction to Polymorphism

Polymorphism refers to the ability to allow objects of different types to respond to the same method call. In C++, this is accomplished through inheritance and virtual functions.

Destructor

The destructor is a special member function associated with a class that is automatically called when an object of that class is destroyed. It is responsible for freeing any memory or resources allocated by the object.

The role of destructor in polymorphism

When a derived class object is created, memory will be allocated to store data members unique to the derived class. However, when the derived class object is destroyed, the memory of the base class also needs to be released. The destructor ensures this by calling the base class destructor.

Practical case

Consider the following code:

class Base {
public:
    Base() { std::cout << "Base constructed" << std::endl; }
    virtual ~Base() { std::cout << "Base destructed" << std::endl; }
};

class Derived : public Base {
public:
    Derived() { std::cout << "Derived constructed" << std::endl; }
    ~Derived() { std::cout << "Derived destructed" << std::endl; }
};

int main() {
    Base* base = new Derived();
    delete base;
    return 0;
}

Output:

Base constructed
Derived constructed
Derived destructed
Base destructed

In this example , the Derived class is derived from the Base class. When a Derived object is created via the new operator, both the Derived and Base constructors are called. When the object is destroyed through the delete operator, the Derived destructor will be called first to release the memory of the Derived class. Then, the Base destructor will be called to release the memory of the Base class.

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