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Sfpiano

Dynamic 2-dimensional arrays

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Here''s how I set up my array:
class lodData{
...
short rg_iHeightArray**;
}

lodData[0].rg_iHeightArray = new short* [128];
		int qw;
		for(qw=0; qw<128; qw++)
			lodData[0].rg_iHeightArray[qw] = new short[128];
 
But when I try to do this: lodData[0].rg_iHeightArray[0][0] = 3; I get an access violation.

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This is just a guess, but could it be an operator precedence issue?
What happens if you try:
lodData->rg_iHeightArray[0][0] = 3;




Remember: Silly is a state of Mind, Stupid is a way of Life.
-- Dave Butler

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Same problem. A weird thing is that when I initialise the array, instead of having a value of some huge negative number, it has a value of -12851.

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i just made a templete class for this


#ifndef ARRAY2D_H
#define ARRAY2D_H

template <class item>
class TArray2D
{
public:
// Constructors

TArray2D(void): mLoaded(false), mWidth(0), mHeight(0), mItems(NULL){;}
TArray2D(unsigned int Width, unsigned int Height){Create(Width, Height);}
// Copy Constructor

TArray2D(const item& FromCopy);
// Destructor

~TArray2D(void){Destroy();}

// Create and Destroy our array

bool Create(unsigned int Width, unsigned int Height);
void Destroy(void);

// Accessor functions

inline bool IsLoaded(void){return mLoaded;}
inline unsigned int GetHeight(void){return mHeight;}
inline unsigned int GetWidth(void){return mWidth;}
inline unsigned int GetSize(void){return mWidth * mHeight;}
inline item& GetCell(unsigned int X, unsigned int Y){return mItems[Y * mWidth + X];}
inline item& GetCell(unsigned int Index){return mItems[Index];}

// Helper functions

void Fill(const item& FillItem);

private:
item* mItems;
unsigned int mWidth;
unsigned int mHeight;
bool mLoaded;
};

// Implamentation -----------------------------------------------

template <class item>
TArray2D<item>::TArray2D(const item& FromCopy)
{
int size = sizeof(FromCopy);
memcpy(this, FromCopy, size);
}

template <class item>
bool TArray2D<item>::Create(unsigned int Width, unsigned int Height)
{
Destroy();
mWidth = Width;
mHeight = Height;
mItems = new item[mWidth * mHeight];
mLoaded = true;
return false;
}

template <class item>
void TArray2D<item>::Destroy(void)
{
if (mItems != NULL)
delete[] mItems;

mItems = NULL;
mWidth = mHeight = 0;
mLoaded = false;
}

template <class item>
void TArray2D<item>::Fill(const item& FillItem)
{
for (unsigned int i = 0; i < mWidth * mHeight; ++i)
{
mItems[i] = FillItem;
}
}

#endif

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Ah, I''ve seen that value many, many times. VC++ initializes every byte of data-page and heap memory to 0xCD. -12851 is two''s-complement of 0xCDCD. Why were you expecting only gigantic negative numbers from what is normally near-random values?

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