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From: chin@sg1.chem.upenn.edu (Chin Wu)
Newsgroups: comp.lang.c++
Subject: PolyMorphism
Message-ID: <CHIN.90Apr9174555@sg1.chem.upenn.edu>
Date: 9 Apr 90 21:45:55 GMT
Sender: news@netnews.upenn.edu
Distribution: comp
Organization: University of Pennsylvania, Philadelphia, PA
Lines: 45


    If we use a Base pointer to construct a Derived object, will the
Derived destructer be used when been deleted? I have used the
following code to explore:
--------------------------
// test derived constructer and destructer

#include <stream.h>

class Base
{
  public:
    Base() { cout << "This is base constructer\n";};
    ~Base() { cout << "This is base destructer\n";};
};

class Derived : public Base
{
  public:
    Derived() { cout << "This is derived constructer\n";};
    ~Derived() { cout << "This is derived destructer\n";};
};

main()
{
    Base* test;

    test = new Derived;
    delete test;
}    
----------------------------
And the output as follow:

This is base constructer
This is derived constructer
This is base destructer

So the derived destructer won't be called if we construct the Derived
object by Base pointer. But isn't it more natural to call both? If I
misunderstood the C++, is there anyway you can call Derived class
destructer?

ps: I am using GNU G++, maybe AT&T behave differently.
--
chin@sg1.chem.upenn.edu