can't delete array that is class field

Question

I have class cAuthorisation that manages array of strAuthorisation function resize prepares aray for next record.

During resize , on line delete [] data; I have crash.

struct strAuthorisation 
{ 
double Amount; 
}Authorisation;

class cAuthorisation { 
public: 
    int size; 
    strAuthorisation *data; 
cAuthorisation ()
{
    size=0;
}

~cAuthorisation()
{

};

void Add(strAuthorisation )
{
    resize();
    data[size]=*value;
}

void resize() 
{
    strAuthorisation *a = new strAuthorisation[5];
    size_t newSize = size + 1 ;
    strAuthorisation *newArr = new strAuthorisation[newSize];
    memcpy( newArr, data, size * sizeof(strAuthorisation) );

    size = newSize;

    delete [] data;
    data = newArr;
}
} Authorisations;

Why it is not possible delete class array?

You should also be doing a check if you need to resize when you `Add` instead of resizing every single time. And you have a memory leak in `resize` where you aren't deleting `a` — Dan F, Jul 17 '12 at 13:20

score 7 · Answer 1 · edited May 23 '17 at 12:27

It crashes because data is an unitialised pointer. delete[] on a null pointer is safe (no-op) so initialise data in the constructor:

cAuthorisation() : size(0), data(0) {}

Note that the class as it stands is violating the rule of three.

Unsure if this is a learning exercise, if it is not use std::vector<strAuthorisation>. The std::vector will dynamically grow as required and automatically destructed when it goes out of scope.

score 4 · Answer 2 · answered Jul 17 '12 at 13:20

4

You have not initialized the data pointer. So you are making something like this:

Foo *data;
delete [] data;

answered Jul 17 '12 at 13:20

Andrew

24,218
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Torsten Robitzki · Answer 3 · 2012-07-17T14:13:45.583

0

"data" is a pointer who's value was never initialized.

edited Jul 17 '12 at 14:13

answered Jul 17 '12 at 13:21

Torsten Robitzki

3,041
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can't delete array that is class field

3 Answers3