De-allocating a variable using "delete"

[MattWoberts]

Hi,

I think this is a simple question - I just can't find any reesources to help me.

I have an array called i, in my class. I need to de-allocate using delete, but only if it has been allocated in the first place (it may not be allocated in the classes life).

My class destructor is pretty simple:

CInterval::~CInterval()
{
delete [] i;
}

I thought this would work:

CInterval::~CInterval()
{
if )i != null)
delete [] i;
}

But, it doesn't!

Any ideas?

 

[SulikSlayer]

Well, it depends on a type of your array.
If it is a pointer to a simple type (such as int, char etc.) you should write

delete i;

If it is a static array such as

int i[10];

you don't have to delete it at all.

I can assume that the same works when your i is an array of complex classes (having their own destructors), i.e. you don't need to delete them manually.
However, I'm not very sure with the last case.

Hope that'll help.

 

[MattWoberts]

It all makes sense, but my particular problem is that my array is dynamically allcoated with the new operator.

The problem is: the array allocation may never occur, so hwo do I first check that there is anything to deallocate (delete) before I delete it?

Thanks

 

[mingis]

Assign initial value NULL to that pointer in constructor.

 

[MattWoberts]

Of course!

Thanks!!

 

[palbano]

Actually if it is set to NULL it is perfectly legal to delete it ONE time.


class foo{
char* buf;
public:
foo() : buf(NULL){}
~foo(){ delete [] buf; }
}

 

[BoulderBum]

for this situation:

char *i = new...

you can use:

delete[] i;