Try this:
N = 10 ;
poly =[5 8 0];
for k = 1:N-1;
A = sum(poly);
B = mod(A,N);
fprintf('At iteration %d, A = %d, and B = %d\n', k, A, B);
end
You'll see
At iteration 1, A = 13, and B = 3
At iteration 2, A = 13, and B = 3
At iteration 3, A = 13, and B = 3
At iteration 4, A = 13, and B = 3
At iteration 5, A = 13, and B = 3
At iteration 6, A = 13, and B = 3
At iteration 7, A = 13, and B = 3
At iteration 8, A = 13, and B = 3
At iteration 9, A = 13, and B = 3
It displays A and B at every one of the 9 iterations, and you can see that they're all the same since A and B never are assigned anything that depends on the iteration number at all.
