# Decimal: Decimal numbers with variable precision

[ bsd3, library, math ] [ Propose Tags ]

A decimal number has an integer mantissa and a negative exponent. The exponent can be interpreted as the number of decimal places in the value.

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Versions [RSS] 0.1.0, 0.2.0, 0.2.1, 0.2.2, 0.2.3, 0.3.1, 0.4.1, 0.4.2, 0.5.1, 0.5.2 changelog.md base (>=4 && <5), deepseq [details] BSD-3-Clause Paul Johnson, 2013, 2018. Paul Johnson paul@cogito.org.uk Math https://github.com/PaulJohnson/Haskell-Decimal by PaulJohnson at 2018-01-03T15:33:05Z Arch:0.5.2, Debian:0.5.1, Fedora:0.5.2, LTSHaskell:0.5.2, NixOS:0.5.2, Stackage:0.5.2, openSUSE:0.5.2 20416 total (138 in the last 30 days) (no votes yet) [estimated by Bayesian average] λ λ λ Docs available Last success reported on 2018-01-03

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Fixed-precision decimal numbers, where the precision is carried with the numbers at run-time.

The Decimal type is mainly intended for doing financial arithmetic where the number of decimal places may not be known at compile time (e.g. for a program that handles both Yen and Dollars) and the application must not drop pennies on the floor. For instance if you have to divide $$10 between three people then one of them has to get$$3.34.

The number of decimal places in a value is represented as a Word8, allowing for up to 255 decimal places. Functions preserve precision. Addition and subtraction operators return a result with the precision of the most precise argument, so 2.3 + 5.678 = 7.978. Multiplication and division use whatever precision is necessary up to 255 decimal places.

## QuickCheck Specification

Data.Decimal includes a set of QuickCheck properties which act as both tests and a formal specification. To run the tests do:

cabal configure --enable-tests cabal build cabal test

or

stack test