How do I use for end statements?

I've asked this question before, but I'm still not grasping how to use for-end statements. I have a random vector v, and I need to find the number of negative elements, positive elements, the sum of all positive elements, and the product of all elements between a specific range, all within the same vector. I know how to do this without using a for-end statement with no problem, but I have to know how to do this using a for-end statement and I'm having some difficulty.

Answer 1

[Walter Roberson]

neg_count = 0;
pos_count = 0;
pos_total = 0;
range_prod = 1;
for idx = 1 : length(v)
  if v(idx) is negative
     neg_count = neg_count + 1;
  end
  ...
  if v(idx) is in the particular range
     range_prod = range_prod * v(idx);
  end
end

[Noah Kebschull]

That helps a lot, thanks.