Re: Rounding error when converting from double to int


"Gordon Burditt" <gordonb.9dw2o@xxxxxxxxxxx> ha scritto nel messaggio
news:L4ednasuFM67lxrXnZ2dnUVZ_uSdnZ2d@xxxxxxxxxxxxxxxxxxxxxxxxx
Do your calculation that generates the fractions in integers. I'm
assuming here that negative numbers are not involved. For example,
if you have $9.51 (represented as 951 cents) and you need to take
8.875% of it (suppose it's a sales tax calculation), multiply 8.875%
by one million and get 88750. (This presumes that sales tax rates
are always multiples of 0.0001%). Be sure *NOT* to put 8.875% into
a double. Represent it as 88750 / 1000000, and treat numerator and


first of doing this division, from 8.875 -> 88750 is there one rounding?

I told you above *NOT* to put the percentage into a double in the first
place, so there is no rounding.

Is the above mean "8.875" have be to put, form input to one integer?

if for example we have 8.795% and it is rappresented in double like
8.79499999999999999

DO NOT put that value into a double.

the result afther the "->" will be 87949 of 87950?

The multiplication should be done in mathematics, not C.

"in mathematics" means using only unsigned types?



.

Relevant Pages

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