Safe removal of the array - delete[]

[zsukal]

Hello.
I have problem. I write class witch array int.
I must check that array exist, because i must delete it.

// if i use it first time - array not exist i have error
void deleteArr(){
 if (arr != NULL)
  delete[] arr;
}

void setArr(){
 deleteArr();
 int* arr = new int[5];
}

[zsukal]

In constructor i must write:

arr = NULL;

;-)

[S6k9GNh0]

Um, wut? I'm pretty sure thats not what you do and is a large source of memory leaks...

[Galik]

void deleteArr(){
 if (arr != NULL)
  delete[] arr;
}

the if statement is not necessary. If arr is set to 0 then delete[] will simply ignore it:

void deleteArr(){
  delete[] arr;
}

That does the same thing.

[Galik]

arr = NULL;

I believe in C++ its considered better to use 0 rather than NULL:


arr = 0;

In a constructor, this should be done in the 'initializer list':

class Test
{
    int* arr;
public:
    Test() : arr(0)
    {
    }
};

[S6k9GNh0]

Its the same exact thing. It doesn't matter.

And I was under the impression that you were for some reason assigning a data address and then assigning NULL. Not sure why I thought that.