No. You must explictly destroy the contained object in the
destructor of the container.
The following code has a container bar which holds foo. bar's
constructor new's a copy of foo, but it's destructor does not
explicitly destroy that object.
--[ begin code ]---
#include <stdio.h>
#include <stdlib.h>
class foo {
public:
foo( ) { printf("constructor foo( ) called.\n"); }
~foo( ) { printf("destructor ~foo( ) called.\n"); }
};
class bar {
public:
bar( ) { printf("constructor bar( ) called.\n");
fp = new foo( ); }
~bar( ) { printf("destructor ~bar( ) called.\n"); }
foo* fp;
};
void main( ) {
bar *bp;
bp = new bar();
delete bp;
}
--[ end code ]---
--[ begin output ]--
constructor bar( ) called.
constructor foo( ) called.
destructor ~bar( ) called.
--[ end output ]--
If the destructor were autmatically called, then you would see
"destructor ~foo( ) called." in the output. You must explictly
destroy objects you create. You can get around this by using
the auto_ptr class which will destroy pointers when the auto_ptr
object goes out of scope.
traff
( this was with egcs-1.1.1 patched up to pgcc-2.91.60 )
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Suresh
> Sent: Thursday, January 21, 1999 6:03 AM
> To: holotko
> Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]
> Subject: Re: C++ Destructor Question
>
>
> Hi,
> The destructor is automatically called when the
> object in question is no longer needed. Such as
> an object is created inside a function locally and
> when the function returns the object gets killed with
> the destructor executed. Hence we dont call the
> destructor explicitly.
>
> And in java I feel the garbage collection concept is
> implemented quite strong and rarely do we use explicit
> deallocation.
>
> Cheers,
> Suresh
> Wipro-Nortel Networks
> Bangalore
> >
> >
> >Being spoiled by Java's garbage collector leads me to this quick
> >question again concerning constructors in C++.
> >
> >If I allocate memory via "new" using a constructor
> >
> >i.e.
> >
> > class Foo
> > {
> > Foo()
> > { word = new char[LENGTH + 1]; }
> >
> > ~Foo()
> > { delete word; }
> >
> > ...
> > }
> >
> >When I create an object of class Foo memory will be allocated for the
> >char buffer "word". Now when the object is no longer needed must I
> >make an explicit call to the destructor ~Foo() to destroy the object
> >and subsequently call "delete", or, is the destructor somehow called
> >automatically when the object is no longer needed,i.e. outside of
> >it's scope?
> >
> >Even in Java there are times when it is up to you to destroy an object
> >and/or free memory used for that object, depending on how the object
> >is/was created and an method equivalent of a destructor is required...
> >The garbage collector is not always adequate.
> >
> >Thanks...
> >
> >Sincerely,
> >
> >/John <[EMAIL PROTECTED]>
> >
> >
> >--
> >email: [EMAIL PROTECTED]
> >Local mailserver <landreau.ruffe.edu> , remote <ns.computer.net>
> >
> >There is a great alternative to war, it's called Peace.
> >
>
>
> --
>
