🚀 go-pugleaf

Ron Reynolds <ron@ronreynolds.com> wrote:

> using doubles is a requirement, but most values we work with are
> currency values (or stock prices) and the docs indicate that
> float is good for up to 6 significant decimal digits, so i think
> i'm safe on the precision loss.  

It is never safe to use floating point numbers for currency when you 
have to track the value correct to the penny.

When expressed in binary, basic currency components like 1/10 and 1/100
are irrational numbers!  Just as the value of pi is irrational in decimal,
1/10 is irrational in binary. You will always have roundoff problems if you
use a floating-point number.

> i'd really like to know how would one of you guys would have
> solved this same problem.

Use bigdecimal or integers, and manipulate the values in pennies, not
dollars.  Convert to dollars only when displaying the balance in a UI.

-- 
Joi Ellis (TeamB) 
No direct email, please.
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