2D array help

Code:

int **pixel;	
rows = numRows;
columns = numCols;

	pixel = new int *[rows];
	for(int i = 0; i < rows ; i++)
	{
		pixel[i] = new int [columns];
		for(int j = 0; j < columns; j++)
		
                pixel[i][j] = 0;
	}

This bit is fine, and is in general when filling a 2d array from start through to finish.

What if I want to then fill this 2d array with meaningful data within some statements:

Code:

int i=0;
int j=0;

for (int x=0;x<rows;x++){
    for (int y=0;y<columns;y++){
 
          pixelvariable++;
          if (somecondition_true){
               pixel[i][j] = *pixelvariable;
               if (j < (pixelColumnSize-1) j++ //THIS PART IS THE PROBLEM??
               else j=0; i++;
     }
}

The code above is very rough as I do not have the problem at hand...I want to be able to fill that 2d array given a certain condition, therefore i need a way to control the i and j variables of the 2d array.

Is there a better way? the above does not work at the moment.

You should complete your code with appropriate braces. I do not know what you intended to do.

Code:

if (j < (pixelColumnSize-1) j++ //THIS PART IS THE PROBLEM??
else j=0; i++;

Did you mean:

Code:

if (j < (pixelColumnSize-1)) {
    j++;
}
else {
    j=0;
    i++;
}

?

Yes, that is how it is present in the actual code, thereabouts, with a few other checks...Sorry, I done it like that since I was just roughly formatting the code.

Be more specific.
Why doesn't it work? Does it compile? Why not?
You didn't provide the condition, I don't know what pixel_variable is. You want a better way while the current one does not even work.

It does not work (compiles but throws memory exception), but I could get it to work eventually I think by just doing multiple checks. The variable pixel_variable is irrelevant in the context of this problem. It could just be a random Int.

The second If statement attempts to navigate the 2d array correctly.

Code:

for (int x=0;x<rows;x++){
    for (int y=0;y<columns;y++){
        if (somecondition_true){
            pixel[i][j] = *pixelvariable++;
            if (j < (pixelColumnSize-1)) {
                j++;
            }
            //THIS PART IS THE PROBLEM??
            else {
                j=0;
                i++;
            }
        }
    }
}

I think your problem was related to how you chose to update pixelvariable. It doesn't have to be this, but it must be equivalent in effect to this, if it works.