C++ newbie: loop not filling a matrix/array with values from another matrix?

[Antst]

Hi everyone:

I have written a loop (below). What I want is to fill a 2-dimensional array called instantAct with values from another 2-d array called mS.

Here's the problem... instantAct and mS have different dimensions. But they have the same number of values. I want my loop to take certain values from mS and put them in instantAct. The problem is that instantAct is remaining empty. I have checked mS and there are values in it, and my indexing to get them is correct.

My question is, why is instantAct still empty? Is it NOT possible to use a complicated loop to equate two arrays? Thanks a lot for any help! Here is my code:

for ( int i = 0; i < array.NumberOfIntervals(); i++ )
{
for (int j = 0; j < nC; j++)
{
for (int k = (nC * xAg) - nC; k < (nC * xAg); k++)
{
instantAct[ i ][ j ] = mS[ i ][ k ];
}
}
}

 

[modulo_function]

If they have the same number of elements then you can use a single loop variable and some artihmetic tricks to get the correct row and col indices.

If Ia is [rmax][cmax]

then make a loop, k, that goes from 0 to rmax*cmax-1

get r and c for a[r][c] by

r = k/cmax;
c = k%cmax;

sketch a little matrix and verify that that's correct

Same thing for the other matrix but rmax, cmax would be different, right.

+add
This works and only involves cmax because 2-d arrays are stored as 1-d row arrays.

++add
I wonder why Mr Conspiracy thinks what he described is 'easier'. Did that seem easier to anyone?

Here's the code:

for( in k=0; k<rmax*cmax; k++ )
...a1[k/c1max][k%c1max] = a2[k/c2max][k%c2max];
}

That's it!