#include <iostream>

class X
{
        public:
                ~X();
};

X::~X()
{
        cout << "X dest. called" << endl;
}


int main
{
        X **a;
        a = new X* [2];
       a[0] = new X[2];
       a[1] = new X[2];
        delete [] a[0];
        delete [] a[1];

        delete [] a;  // <------------ (1)
        return (0);
}



in (1), can i use
    delete a;
instead of
    delete []a;
???

thx~



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<hkphoton@singnet.com.sg> wrote in message
news:3885C6CA.C87C6451@singnet.com.sg...
>
> int main
> {
>         X **a;
>         a = new X* [2];
>        a[0] = new X[2];
>        a[1] = new X[2];
>         delete [] a[0];
>         delete [] a[1];
>
>         delete [] a;  // <------------ (1)
>         return (0);
> }
>
> in (1), can i use
>     delete a;
> instead of
>     delete []a;
> ???

No. It can invoke undefined behaviour. You might get away with it,
especially with simple types, but in general no.

As a rule, if new has [], so must the corresponding delete.

Ric




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Hi,
In article <3885C6CA.C87C6451@singnet.com.sg>,
  hkphoton@singnet.com.sg wrote:
> int main
> {
>         X **a;
>         a = new X* [2];
>         delete [] a;  // <------------ (1)
> }
>
> in (1), can i use
>     delete a;
> instead of
>     delete []a;

No, you cannot: Every array object allocated with 'new' has to be
release using 'delete[]'. Using 'delete' instead would result in
undefined behavior. It does not matter whether the type is built-in, a
POD, or some class. In all cases you have to follow this rule.
--
<mailto:dietmar.kuehl@claas-solutions.de>
homepage: <http://www.informatik.uni-konstanz.de/~kuehl>


Sent via Deja.com http://www.deja.com/
Before you buy.


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hkphoton@singnet.com.sg wrote:
>
> #include <iostream>
>
> class X { ... };
>
> int main
> {
>         X **a;
>         a = new X* [2];
>        a[0] = new X[2];
>        a[1] = new X[2];
>         delete [] a[0];
>         delete [] a[1];
>
>         delete [] a;  // <------------ (1)
>         return (0);
> }
>
> in (1), can i use
>     delete a;
> instead of
>     delete []a;

You must use the form of delete that matches the form of new.
Since 'a' was allocated with new[], it must be deallocated
with delete[]. The results of your program are otherwise undefined.

In particular, it is possible for new and new[] to use different
memory pools. In that case, 'delete a' would try to return the
storage to the wrong pool.

--
Steve Clamage, stephen.clamage@sun.com

---
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hkphoton@singnet.com.sg wrote:
>
>
>         a = new X* [2];
>         delete [] a;  // <------------ (1)
> in (1), can i use
>     delete a;
> instead of
>     delete []a;

No.  You must always use delete[] when you use new T[];

---
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