Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!ulysses!andante!alice!shopiro
From: shopiro@alice.UUCP (Jonathan Shopiro)
Newsgroups: comp.lang.c++
Subject: Re: deallocating an array of objects
Message-ID: <9500@alice.UUCP>
Date: 16 Jun 89 21:05:45 GMT
References: <1245@cadillac.CAD.MCC.COM>
Organization: AT&T Bell Laboratories, Murray Hill NJ
Lines: 49

In article <1245@cadillac.CAD.MCC.COM>, rpj@redcloud.cad.mcc.com (Rich Johns) writes:
- 
- Assume:
- 
- class Foo {
-  Foo() { /*stuff*/}
-  ~Foo() { /* stuff*/}
- };
- 
- main() {
-  Foo** fooArray = 0;
-  fooArray = new Foo*[100];  // fooArray points to 100 uninitialized pointers
- 
- // do something
- 
- }
- 
- My question has to do with deallocating fooArray. If I am not concerned with
- deleting the contents of fooArray (the 100 Foos), it seems like:
Your problem is fooArray does not contain 100 Foos, it contains 100 pointers to
Foo.
- 
- delete fooArray;
This works if the delete mechanism doesn't need to know how the size of
the object being deleted.  (Universally true, I believe).
- 
- is correct. If I did  want to delete the 100 Foos, would this be correct:
- 
- delete [100]fooArray;
This works too, but it doesn't delete the pointed-to Foos.
- 
- or would I have to:
- 
-   for (int i = 0; i < 100; i++) {
-     delete fooArray[i];
-   }
This deletes the pointed-to Foos (and they better be there to delete)
-   delete fooArray;
This deletes the array of pointers.  Use the more explicit
``delete [100] fooArray'' as a good habit.
- 
- Would the answer be different if Foo does not have a
- constructor and destructor?
no.

-- 
		Jonathan Shopiro
		AT&T Bell Laboratories, Warren, NJ  07060-0908
		research!shopiro   (201) 580-4229