What is a virtual destructor explain with an example?

What is a virtual destructor explain with an example?

Deleting a derived class object using a pointer of base class type that has a non-virtual destructor results in undefined behavior. To correct this situation, the base class should be defined with a virtual destructor. For example, following program results in undefined behavior.

How does a virtual destructor work?

In simple terms, a virtual destructor ensures that when derived subclasses go out of scope or are deleted the order of destruction of each class in a hierarchy is carried out correctly. If the destruction order of the class objects is incorrect, in can lead to what is known as a memory leak.

What is a pure virtual destructor?

Pure virtual destructor in C++ Yes, it is possible to have pure virtual destructor. This means that a derived class’ destructor will be invoked first, then base class destructor will be called.

What is the difference between destructor and virtual destructor?

The only difference between Virtual and Pure Virtual Destructor is, that pure virtual destructor will make its Base class Abstract, hence you cannot create object of that class. There is no requirement of implementing pure virtual destructors in the derived classes.

Why is destructor virtual?

Virtual destructors in C++ are used to avoid memory leaks especially when your class contains unmanaged code, i.e., contains pointers or object handles to files, databases or other external objects. A destructor can be virtual.

When should a destructor be virtual?

In particular, here’s when you need to make your destructor virtual:

1. if someone will derive from your class,
2. and if someone will say new Derived, where Derived is derived from your class,
3. and if someone will say delete p, where the actual object’s type is Derived but the pointer p’s type is your class.

Is virtual destructor inherited?

5 Answers. Yes, they are the same. The derived class not declaring something virtual does not stop it from being virtual. There is, in fact, no way to stop any method (destructor included) from being virtual in a derived class if it was virtual in a base class.

Why do I need virtual destructor?

When should a destructor be declared as virtual?

Virtual keyword for destructor is necessary when you want different destructors should follow proper order while objects is being deleted through base class pointer.

What are virtual destructors in C++?

Do I need virtual destructor?

When would you use a virtual destructor?

What is the purpose of a virtual destructor?

Virtual destructors : – The explicit destroying of object with the use of delete operator to a base class pointer to the object is performed by the destructor of the base-class is invoked on that object. – The above process can be simplified by declaring a virtual base class destructor.

Can a base class destructor be a virtual constructor?

Destructors in the Base class can be Virtual. Whenever Upcasting is done, Destructors of the Base class must be made virtual for proper destrucstion of the object when the program exits. NOTE: Constructors are never Virtual, only Destructors can be Virtual. Lets first see what happens when we do not have a virtual Base class destructor.

How are pure virtual destructors legal in C + +?

Pure Virtual Destructors are legal in C++. Also, pure virtual Destructors must be defined, which is against the pure virtual behaviour. The only difference between Virtual and Pure Virtual Destructor is, that pure virtual destructor will make its Base class Abstract, hence you cannot create object of that class. There is no requirement of

What happens if base destructor does not use virtual keyword?

Note: If the base class destructor does not use a virtual keyword, only the base class destructor will be called or deleted its occupied space because the pointer object is pointing to the base class. So it does not call the derived class destructor to free the memory used by the derived class, which leads to memory leak for the derived class.