C / C++ / MFC

8-Nov-05 22:01

I am using the following code to allocate dynamic double dimensional array

double **ImagePro;
try
{
ImagePro = new double*[width];
for(int i = 0; i < height; i++)
{
ImagePro[i] = new double[width];
}
}
catch(CMemoryException* ex)
{
ImagePro = NULL;
ex->ReportError();
return FALSE;
}

and for deletion

for(int i = 0; i < height; i++)
{
delete ImagePro[i];
}
delete ImagePro;

return TRUE;

My problem is whenever the height is greater than width I get assertion error message

Pls Help

kakan8-Nov-05 22:23

8-Nov-05 22:23

Hello.

Try changing:
ImagePro = new double*[width];
to
ImagePro = new double*[height];

Cedric Moonen8-Nov-05 22:32

Cedric Moonen

8-Nov-05 22:32

Did you try this ?

for(int i = 0; i < height; i++)<br />
{<br />
delete[] ImagePro[i];<br />
}<br />
delete[] ImagePro;

And wich part of the code is asserting ?

Arrun8-Nov-05 23:06

8-Nov-05 23:06

delete[] ImagePro is not working

I get assertion in "delete ImagePro;"

kakan8-Nov-05 23:11

8-Nov-05 23:11

You should, since
delete ImagePro[0];
Is the same as
delete ImagePro;

So when you the delete ImagePro, its already deleted.

Arrun8-Nov-05 23:40

8-Nov-05 23:40

It works fine when the height and width are equal or if the height is less than width
The error occurs only when the height is greater than the width.

BoundsChecker displays an error message "Dynamic memory overrun"

kakan9-Nov-05 0:07

9-Nov-05 0:07

Hello.

See my earlier post. You allocate <width> no of items twice.
You don't use <height>, except in the allocating loop.

Since you allocate room for <width> items in your table.
So it's natural that you go out of bounds if height is bigger than what you allocated (which is <height> items).

Kakan

Arrun9-Nov-05 0:27

9-Nov-05 0:27

so how should I allocate and delete dynamic memory when the width and height are different.

help me with some code.

kakan9-Nov-05 0:32

9-Nov-05 0:32

Sorry, I'm at work and have work to do.
But there is HEAPS of source code for dynamic 2-dimensional arrays out there.
Serach at CodeProject and/or Google.
I think you need to find a working example to start with.

Good luck.
Kakan.

kakan9-Nov-05 2:13

9-Nov-05 2:13

Hello again. I couldn't let go of your problem. Smile | :)

I found a lot of suggestions at experts exhange, at:
http://www.experts-exchange.com/Programming/Programming_Languages/Cplusplus/Q_21442835.html[^]

This example looks interesting, and complete:

<br />
template < typename T ><br />
T **Allocate2DArray( int nRows, int nCols)<br />
{<br />
    T **ppi;<br />
    T *pool;<br />
    T *curPtr;<br />
    //(step 1) allocate memory for array of elements of column<br />
<br />
    ppi = new T*[nRows];<br />
<br />
    //(step 2) allocate memory for array of elements of each row<br />
    pool = new T [nRows * nCols];<br />
<br />
    // Now point the pointers in the right place<br />
    curPtr = pool;<br />
    for( int i = 0; i < nRows; i++)<br />
    {<br />
        *(ppi + i) = curPtr;<br />
         curPtr += nCols;<br />
    }<br />
    return ppi;<br />
}<br />
<br />
template < typename T ><br />
void Free2DArray(T** Array)<br />
{<br />
    delete [] *Array;<br />
    delete [] Array;<br />
}<br />
<br />
int main()<br />
{<br />
    double **d = Allocate2DArray<double>(10000, 10000);<br />
    d[0][0] = 10.0;<br />
    d[1][1] = 20.0;<br />
    d[9999][9999] = 2345.09;<br />
    Free2DArray(d);<br />
}<br />

In the main function, you can see how to use the array.
I think you should try it out.

Regards
Kakan