In reply to Sunhee Kim.

The value 0.84 is not contained in the vector, but even if you change &cut to be 0.8 you are not likely to find 0.8 because of the numerical representation of values in finite precision arithmetic. For example, run this code:
diff = 0.8 - the[49]; print diff;

Your example is basically the same as the first example in this article about why you should avoid testing for equality in finite precision computations. For comparisons like this, you can round the computed results before you test for equality, as follows:
the = round(the, 1e-8);