Question

I have a 2d matrix created with the code:

for(i=0; i < size; i++)
{
    for(j=0; j <size; j++)
    {
        a1[i][j] = i+1 + j+2;
    }
}

I am trying to replicate that pattern in a matrix created by:

double*
a = malloc(sizeof(double)*randk*randk);

I can’t seem to figure out how to define that same pattern.

Answer 1

You mean creating the same numeric pattern? That’s just:

for(int i = 0; i < randk; ++i)
  for(int j = 0; j < randk; ++j)
    a[i * randk + j] = i + j + 3;

Or if you prefer a single loop:

for(int i = 0; i < randk * randk; ++i)
  a[i] = (i / randk) + (i % randk) + 3;