^{33}Don’t confuse double variables with the real numbers. double variables take values that
are ﬁnite approximations of real numbers and take values that are a subset of the rational
numbers. This approximation becomes better by increasing the amount of memory allocated
to store them. In most computing environments, doubles are allocated 8 bytes of
memory, in which case they approximate real numbers with, more or less, 17 signiﬁcant
digits.