Ibrahim - what are you trying to do here? Just display (with disp) a message depending upon whether an element is a zero or not? The simplest and least efficient way to do this is with a loop
test = [5;6;0;-1;0];
for k = length(test)
if test(k) == 0
I don't think that is what you really want though so you may need to provide more details. I also suspect that you shouldn't need to use a for loop and that may be the case depending upon the details you provide.