Java Reference
In-Depth Information
The static method IEEEremainder calculates remainder as defined by the
IEEE 754 standard. The remainder operator % , as described in " Floating-
Point Arithmetic " on page 202 , obeys the rule
(x/y)*y + x%y == x
This preserves one kind of symmetry: Symmetry around zero. That is,
if x%y is z , then changing the sign of either x or y will change only the
sign of z , never its absolute value. For example, 7%2.5 is 2.0 , and -7%2.5
is -2.0 . The IEEE standard defines remainder for x and y differently, pre-
serving symmetry of spacing along the number linethe result of IEEEre-
mainder(-7,2.5) is 0.5 . The IEEE remainder mechanism keeps resulting
values y units apart, as contrasted with the remainder operator's sym-
metry around zero. The method is provided because both kinds of re-
mainder are useful.
The static method random generates a pseudorandom number r in the
range 0.0 r < 1.0. More control over pseudorandom number genera-
tion is provided by the Random class, as you learned on page 639 .
The algorithms used in StrictMath are those defined in the FDLIBM "C"
math library; if you need a complete understanding of these issues, con-
sult The Java Language Specification , Third Edition.
See " java.math Mathematics " on page 722 for brief coverage of some
other math-related classes.
Exercise 22.15 : Write a calculator that has all Math or StrictMath func-
tions, as well as (at least) the basic operators + , - , * , / , and % . (The
simplest form is probably a reverse Polish stack calculator because op-
erator precedence is not an issue.)
Computers are uselessthey can only give you answers.
Pablo Picasso
Search WWH ::




Custom Search