C++ const array change without reason - c++

Question

I have a problem with a piece of code. I'll provide you a simplified version :
class AdvancedImage
{
Image *_source;
int _w;
int _h;
AdvancedImage(const Image *src, const PointFloat corners[], int w, int h)
{
InitializeInstanceFields();
_source = new Image(src->data, src->h, src->w);
_w = w;
_h = h;
PointFloat newPoints[4];
for (int i = 0; i < 4; i++)
{
newPoints[i] = corners[i];
}
/* Initialisation continue... */
}
InitializeInstanceFields()
{
_w = 0;
_h = 0;
}
}
class Image
{
unsigned char *data;
int width;
int height;
int size;
Image(const unsigned char newData[], int h, int w)
{
InitializeInstanceFields();
this->height = h;
this->width = w;
this->size = h * w;
this->data = new unsigned char[this->size];
for (int i = 0; i < this->size; i++)
{
this->data[i] = newData[i];
}
}
}
class PointFloat
{
float X;
float Y;
PointFloat(float x, float y)
{
this->X = x;
this->Y = y;
}
}
And I'm using the AdvancedImage like this :
void myFunction (const Image *img, const PointFloat corners[])
{
AdvancedImage *advImg = 0;
/* Some code */
advImg = new AdvancedImage(img, corners, 15, 30);
/* Code continue */
}
My problem is that the values in corners change after doing the new AdvancedImage. I try to debug, and I saw something I can't explain. In constructor AdvancedImage, corners[0] is {76.0, 45.0}. I added a watch to &corners, in constructor new Image values don't change, but when code return from constructor (goes to line _w = w;) values are now something like {7.7877970e40, 0.2554460e-20}.
I've looked for a solution but nothing do. How can I solve this problem ? Where can it come from ?