From: Michael G. Schwern <schwern@pobox.com>
Date: Tue, 29 May 2001 18:51:32 +0000 (+0100)
Subject: Example of working in integers to avoid floating point errors
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=1affb2ee4597bbf287e792c440907d25929aff2e;p=p5sagit%2Fp5-mst-13.2.git

Example of working in integers to avoid floating point errors
Message-ID: <20010529185132.C706@blackrider.blackstar.co.uk>

p4raw-id: //depot/perl@10301
---

diff --git a/pod/perlfaq4.pod b/pod/perlfaq4.pod
index 069340d..87fd66a 100644
--- a/pod/perlfaq4.pod
+++ b/pod/perlfaq4.pod
@@ -39,6 +39,11 @@ arbitrary-precision decimal numbers with the Math::BigFloat module
 (part of the standard Perl distribution), but mathematical operations
 are consequently slower.
 
+If precision is important, such as when dealing with money, its good
+to work with integers and then divide at the last possible moment.
+For example, work in pennies (1995) instead of dollars and cents
+(19.95) and divide by 100 at the end.
+
 To get rid of the superfluous digits, just use a format (eg,
 C<printf("%.2f", 19.95)>) to get the required precision.
 See L<perlop/"Floating-point Arithmetic">.