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From: todd@pinhead.pegasus.com (Todd Ogasawara)
Newsgroups: comp.lang.perl
Subject: UNIX Perl vs. DOS Perl (arithmetic)?
Message-ID: <1991May23.221206.12903@pinhead.pegasus.com>
Date: 23 May 91 22:12:06 GMT
Organization: Hawaii Medical Service Association
Lines: 47

I wrote a little program that takes data files of a particular format
(fixed record, no delimiters) and calculates various totals to compare to a
trailer record in that file. The program works fine when I run it using
Perl 4.0 PL03 under UNIX (ISC 2.2, System V/386 R3). However, I get wildly
different results when I run the same program (and using the same data
file) under the DOS version of Perl (3.0 PL41). The outputs are attached
below.

Perl 4.0 PL03 under ISC 2.2
*** FROM TRAILER RECORD ***
Total records         26
Total charges       1991.60
Total adjustments   -363.23
Total allowances     880.91

*** FROM REFERENCE RECORDS ***
Total records         26	<== Trailer and calculated figure match
Total charges       1991.60	<== Trailer and calculated figure match
Total adjustments   -363.23	<== Trailer and calculated figure match
Total allowances     880.91	<== Trailer and calculated figure match


Perl 3.0 PL41 under MS-DOS 3.3
*** FROM TRAILER RECORD ***
Total records         26
Total charges        199.16
Total adjustments    -36.32
Total allowances      88.09

*** FROM REFERENCE RECORDS ***
Total records         26	<== Trailer and calculated figure match
Total charges        199.13	<== ERROR of -0.03000000000000114
Total adjustments    -36.29	<== ERROR of 0.03000000000000114
Total allowances      88.04	<== ERROR of -0.04999999999999716

I checked the data file I brought down to DOS and confirmed that it is
identical to the one I used on the UNIX system.

All I am doing is 'substr' segments of 160 byte long records and
accumulating totals. It works fine under UNIX but fails miserably in the
DOS version. Any ideas? I used a MS-DOS based program that I hoped to
replace with the Perl program to double check things under DOS. The old
program returns results that agree with the UNIX Perl program.
-- 
Todd Ogasawara ::: Hawaii Medical Service Association
Internet       ::: todd@pinhead.pegasus.com
Telephone      ::: (808) 536-9162 ext. 7