Integer division always produces a result which is another integer
value: any fractional part is truncated, i.e. rounded towards zero.
This makes it especially important to provide a decimal point at the
end of a real constant even if the fractional part is zero. For
example:
The combination of the two preceding rules may have unexpected
effects, for example:
whereas (-2)**3.0 is an invalid expression as the computer would
try to evaluate the logarithm of -2.0, which does not exist.
Similarly, the expression:
whereas