FAQ 4.1 Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be get


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4.1: Why am I getting long decimals (eg, 19.9499999999999) instead of the numbers I should be getting (eg, 19.95)?

For the long explanation, see David Goldberg's "What Every Computer
Scientist Should Know About Floating-Point Arithmetic"

Internally, your computer represents floating-point numbers in binary.
Digital (as in powers of two) computers cannot store all numbers
exactly. Some real numbers lose precision in the process. This is a
problem with how computers store numbers and affects all computer
languages, not just Perl.

perlnumber shows the gory details of number representations and

To limit the number of decimal places in your numbers, you can use the
"printf" or "sprintf" function. See the "Floating Point Arithmetic" for
more details.

printf "%.2f", 10/3;

my $number = sprintf "%.2f", 10/3;


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