When Destructor is called in C++?

Question

when destructor is called.Is it when delete is used?

Answer 1

In C++ you call the destructor yourself when you no longer need the class, just like any other function. Like a constructor, however; you do not need to have a destructor. If your class has no resources to clean-up after there is no need for a destructor. Poor use of destructors (and other means of clean-up) were a powerful motivation for the garbage collection system used by most other languages.

A destructor in C++ has the same name as the class (like the constructor) but is preceeded by the "~" (tilde) character. So, for the class A, you would have:

A::~A( ) {  //do some cleanup }

Typically, you call the destructor by using the anti-new keyword, delete.

Answer 2

It deconstructs the collected structure. You're looking for Garbage Collection if you want to delete useless used data. It can free up memory and eliminate memory leaks.

Answer 3

Yes, the destructor is called when delete is used; it is also called when a local object goes out of scope. To clarify the latter:

class myClass

{

     myClass(){}

     ~myClass(){}

};

Then, we may say,

void myFunction()

{

     myClass X();

     //do something

}

int main()

{

     myFunction();

     return 0;

}

and the destructor will be called at the end of myFunction, when the object X goes out of scope.

There is often no need to call the destructor directly. If your constructor dynamically allocates memory, for example, and you call your destructor (which de-allocates that memory), and then it is automatically called by the delete operator later, then an error will occur.