It all comes down to the inexactitude in the way computers represent floating point values. By printing the values out with as many digits of precision as you can, you'll see that one value rounds down, and the other rounds up. 

printf "%.17f\n", 40.88050;
40.88049999999999800

printf "%.17f\n", 41.78050;
41.78050000000000400

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The (probable) reason that you see a different result from C, is that you are (probably) using single precision (floats) in your C code, whilst Perl uses double precision. (Probably:)

See Re: Re: Re: Bug? 1+1 != 2 for more information.

Examine what is said, not who speaks.
"Efficiency is intelligent laziness." -David Dunham
"Think for yourself!" - Abigail
"Memory, processor, disk in that order on the hardware side. Algorithm, algorithm, algorithm on the code side." - tachyon

In reply to Re: Rounding error? by BrowserUk
in thread Rounding error? by dracos

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