Solved

virtual destuctor

Posted on 2011-03-04
6
296 Views
Last Modified: 2012-05-11
I have seen following in my appln.

class A {

virtual ~A();
}

class B : public A {
  B()
}

Inside B.cpp, the function ~A() and ~B() both is missing

Shouldn't the base class destructor MUST be defined in child class
0
Comment
Question by:learningunix
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 3
  • 2
6 Comments
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 35039432
Virtual destructors only guarantee for the calling order, nothing else - you don't necessarily have to provide an explicit destructor in a derived class, the compiler will create a default destructor that will then be chained in the sequence - see also http://www.codersource.net/c/c-miscellaneous/c-virtual-destructors.aspx
0
 
LVL 11

Expert Comment

by:DeepuAbrahamK
ID: 35041693
Unlike ordinary member functions, a virtual destructor is not overridden when redefined in a derived class. Rather, it is extended: the lower-most destructor first invokes the destructor of its base class and only then, it is executed.

0
 
LVL 86

Expert Comment

by:jkr
ID: 35041726
DeepuAbrahamK, it's always a good idea to quote your sources: http://www.codeguru.com/forum/archive/index.php/t-445242.html

STLDude
February 4th, 2008, 10:58 AM
A little more info:
Unlike ordinary member functions, a virtual destructor is not overridden when redefined in a derived class. Rather, it is extended: the lower-most destructor first invokes the destructor of its base class and only then, it is executed.
0
Independent Software Vendors: We Want Your Opinion

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 11

Expert Comment

by:DeepuAbrahamK
ID: 35041767

class A
{
public:
      A()
      {
            cout<<"I am inside the ctor : A"<<endl;
      }

    virtual ~A()
      {
            cout<<"I am inside the dtor : A"<<endl;
      }
};

class B:public A
{
public:
      B()
      {
            cout<<"I am inside the ctor : B"<<endl;
      }

    virtual ~B()
      {
            cout<<"I am inside the dtor : B"<<endl;
      }
};


int main () {
  A* a = new B();
  delete a;
}
0
 
LVL 11

Expert Comment

by:DeepuAbrahamK
ID: 35041775
I found that statement is very crisp:
pleasw refer : http://www.devx.com/tips/Tip/12729
0
 

Author Closing Comment

by:learningunix
ID: 35046552
thx
0

Featured Post

Free Tool: Path Explorer

An intuitive utility to help find the CSS path to UI elements on a webpage. These paths are used frequently in a variety of front-end development and QA automation tasks.

One of a set of tools we're offering as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Often, when implementing a feature, you won't know how certain events should be handled at the point where they occur and you'd rather defer to the user of your function or class. For example, a XML parser will extract a tag from the source code, wh…
This article will show you some of the more useful Standard Template Library (STL) algorithms through the use of working examples.  You will learn about how these algorithms fit into the STL architecture, how they work with STL containers, and why t…
The viewer will learn how to pass data into a function in C++. This is one step further in using functions. Instead of only printing text onto the console, the function will be able to perform calculations with argumentents given by the user.
The viewer will learn how to use the return statement in functions in C++. The video will also teach the user how to pass data to a function and have the function return data back for further processing.

724 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question