Is it possible to Overload a Destructor?

[anupam]

Hi Banfa ,
Can we overload destructor ? If yes then plz provide an example ?
If not then why ?

[dhirajrane]

Hi Banfa ,
Can we overload destructor ? If yes then plz provide an example ?
If not then why ?

Answere

#include <stdio.h>
#include <conio.h>
 
class abc
{
public:
abc()
{
printf("Constructor is called\n");
}
~abc()
{
printf("Destructor is called\n");
}
};
class xyz:abc
{
public:
xyz()
{
printf(" Derived Constructor is called\n");
}
~xyz()
{
printf(" Derived Destructor is called\n");
}
};
void main()
{
 
clrscr();
abc *a = new abc();
xyz *x = new xyz();
//abc *b = new xyz();
delete a;
delete x;
//delete b;
getch();
}
 

:)

[anupam]

What was that dhirajrane ? I didn't mean the general constructor and destructor. It was overloaded destructor ( whether we can define more than one destructor in a class or not ) ?

[D_C]

Why would you need to delete something in more than one way? I don't see why it's necessary. Besides, you could always call a single destructor, and conditionally execute whichever destructor you wish.

[Banfa]

Normally (in fact almost always) you never explicitly call the destructor, it is automatically called by the C++ frame work when the object is deleted/goes out of scope. Therefore you would not need to overload the destructor because the frame work always calls the default destructor.

Additionally the C++ standard defines that a conforming compiler only allows for 1 destructor per class.

[anupam]

Thanks all of u.

[uday chandu]

There is no reason for overloading (i mean two function with same name) a destructor in c++, because a destructor is called automatically at last and it will clean the allocated memory. so once allocated memory is de-allocated by one destructor what the need for another function, so only c++ doesn't support destructor overloading .

[sripal]

Uday


i have one Question here,
i got one point we cant overload a destructor,
can we have override destuctor?

[Banfa]

No, destructors (and constructors) are special and you can not over-ride a destructor, nor should you need to.

In a class heirarchy

class Base
{
public:
    Base() {}
    ~Base() {}
};
 
class Derived : public Base
{
public:
    Derived() {}
    ~Derived() {}
};
 

When you construct an instance of Derived after the memory is allocated the first thing that happens is the Base() is called, the Derived() is called.

Destruction happens in a similar manor but reverses the order, first ~Derived() is called, then ~Base() is called.

You can not over-ride ~Base in Derived because the compiler knows that the method starting with ~ is the destructor and that the symbol name following should be the name of the class. There is also no need to over-ride as the Base destructor is going to be called anyway and should be doing the appropriate clean-up for Base.