You define
cube = int.^(1/3)
and then in the next line compare
cube > int^(1/3)
so you are logically comparing
int^(1/3) > int^(1/3)
and logically speaking that is going to always be false. A test that is always false is seldom worth coding.
I did say "logically speaking" though. Real computations with floating point numbers are such that if you calculate an expression in two different but algebraically identical ways, the results are not necessarily going to be exactly the same. But which one would come out higher or lower is quite tricky to predict. It is possible in real computer languages for the test you created to turn out true, and you would have a difficult time figuring out the circumstances in advance.
So, whatever it is you think you are testing there, you'd better test it more robustly.
