Pivoting Gaussian Elimination Coding

I am trying to code a Pivoting Gaussian Elimination code using the algorithm that is posted in the picture. However, on the first iteration under the 2nd for loop(i=...) it is changing A(1,1) to 0 and not A(2,1). Below is the code:

if true
  [n,m] = size(A);
[d,p] = sort(A(:,1),'descend');
for k =1:n-1
  for i = k + 1:n
    z = A(p(i),k) / A(p(k),k);
    A(p(i),k) = 0
    for j = k + 1:n
      A(p(i),j) = A(p(i),j) - z*A(p(k),j);
    end
  end
end

end

[Aveek Podder]

Hi,

p(2) is equals 1 that is the reason why A(p(i),k) = 0 is assigning A(1,1) = 0 instead of A(2,1).