Error in repetition of for loop

Hi guys. I have a code below:

 if p && u <= length(r) && r(p) > r(n) && r(u) >= r(p);
        is_upslope = true;

However, when my u is greater than the length(r), it still gives me is_upslope = true. May I know what is the problem? Thanks

[per isakson]

I cannot reproduce your result. What values do your variables have?

Answer 1

[mbonus]

I believe that your second test of <=length(r) is being tested against a logical 1. This is due to the fact that p && u is being evaluated first which returns a logical 1 assuming they are both nonzero. so the test actually ends up seeing

1 <= length(r) ...

instead you need to format it like this: (also parenthesis while not required make it easier to read)

   if (p <= length(r)) && (u <= length(r)) && (r(p) > r(n)) && (r(u) >= r(p))

[Thorsten]

That's wrong. <= precedes &&

http://de.mathworks.com/help/matlab/matlab_prog/operator-precedence.html

[mbonus]

Oh wow I didn't realize MATLAB did it like that, probably because I always use parenthesis, thank you.