Qt 3D-array with Qt-Objekts like QVector

Question

How can I create a 3D-array only with Qt-Objects? The array should be a 3D-integer-array. I have tried to create a standard 3D-array on the heap. To allocate the memory on the heap works fine. I got an error if i want to deallocate the memory.

const int scalefaktor = 16;
int*** anzPixel3d = new int**[256/scalefaktor];

for (int i = 0; i <= 256/scalefaktor ; i++)
{
    anzPixel3d[i] = new int*[256/scalefaktor];

    for (int k = 0; k <= 256/scalefaktor ; k++)
    {
        anzPixel3d[i][k] = new int[256/scalefaktor];
    }

}





for (int j = 0; j <= 256/scalefaktor ; j++)
{


    for (int m = 0; m <= 256/scalefaktor ; m++)
    {
        delete [] anzPixel3d[j][m];
    }

    delete [] anzPixel3d[j];
}
delete [] anzPixel3d;

For this project I use Qt4.8 and the Qt-Creator 2.7.0. I use the MSVC2010 compiler.

The error-message is: HEAP CORRUPTION DETECTED: after Normal block (#31715) at 0x006E3C0. CRT detected that the application wrote to memory after end of heap buffer.

Answer 1

#include <QCoreApplication>
#include <QVector>
#include <QDebug>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

    int dim_0 = 3;
    int dim_1 = 3;
    int dim_2 = 3;
    int default_val = 0;
    QVector < QVector < QVector< int > > > vec(dim_0,
                                               QVector < QVector <int > > (dim_1,
                                                                           QVector < int > (dim_2, default_val)));

    for( int i = 0; i < dim_0; i++)
    {
        for ( int j = 0; j < dim_1; j++)
        {
            for ( int k = 0; k < dim_2; k++)
            {
                vec[i][j][k] = i*100 + j*10 + k;
            }
        }
    }

    qDebug() << vec;

    return a.exec();
}

Hope that helps.

Answer 2

HEAP CORRUPTION occurred because of <=. If you replace <= to <, your code will work.

const int scalefaktor = 16;
int*** anzPixel3d = new int**[scalefaktor];
for (int i = 0; i < scalefaktor ; i++)
{
    anzPixel3d[i] = new int*[scalefaktor];
    for (int k = 0; k < scalefaktor ; k++)
    {
        anzPixel3d[i][k] = new int[scalefaktor];
    }
}

for (int j = 0; j < scalefaktor ; j++)
{
    for (int m = 0; m < scalefaktor ; m++)
    {
        delete [] anzPixel3d[j][m];
    }
    delete [] anzPixel3d[j];
}
delete [] anzPixel3d;