So what’s the problem?

#include "child.h"

#include <iostream.h>

int main()

{

badparent *c;

int i = 0;

while ( i++ < 5)

{

c = new child();

delete c;

}

}

in child's constructor

in child's constructor

in child's constructor

in child's constructor

in child's constructor

before we had a pointer to “child” here, now we have a pointer to the parent class

?

So what happened to the destructor? How can that be?

Answer: A flaw in the “badparent” class implementation -- it does not define a destructor, so the compiler, who refers to the “child” by the pointer to the parent, never knew that there is a destructor to call.

#ifndef __BADPARENT_H__

#define __BADPARENT_H__

class badparent

{

public:

badparent(){};

};

#endif /* __BADPARENT_H__ */

virtual ~badparent(){};

Adding this line

will convert the bad into a good parent class.

A side note: When I had job interviews with several software companies in Germany, on two occasions I was given this problem to prove that I knew my C++.

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