Subtraction of Decimals in Perl

[Awksome]

Hi All,

I have a simple perl script which subtracts two variables holding decimal numbers and the results is not as expected.

$a = 417747646.853143
$b = 417747646.853142

$c = $a-$b

expected result = $0.000001
actual result = -9.5367431640625e-07

any idea on why I am getting wrong results?

 

[prex1]

You are close (or beyond) the precision available for standard numbers (about 15 decimal figures), so you cannot expect any precision of result in subtraction.
Consider the module Math::BigFloat if you really need that result.

Franco

http://www.xcalcs.com

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[dkyrtata]

If you don't like its appearance, try formatting it like this:

$c=sprintf('%15.6f', $a-$b)

print "c='$c'\n";

c=' 0.000001'