java - Visual Studio Wrong output for float/single operation -

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i'm trying understand how floating point operations give different output. tests performed below result 1; vb.net , c# give different output, whereas java gives different output. has compiler , read what every computer scientist should know floating-point arithmetic confusing, can explain in simple language?

vb.net

dim x single = 1.000001 dim y single = 0.000001  dim result = x - y

output: 0.9999999 click here see output same goes c#

also, while watching variable in visual studio, value of result different outputs, trimmed while printing , 7 9's printed(which understood), dont understand how actual result them 0.99999994 vs floating operation output

update: alright, i'm more interested in how calculation done(removed java stuff)

numbers in visual basic single (or c# float) stored ieee 754-2008. number stored in 32 bits. first bit sign next 8 bits store exponent , next 23 bits store fraction.

first integer part of number converted base 2. fraction converted base 2 , number shifted right exponent matches format:

1.x1..x23 x 2^e

where x1 x23 bits in fraction part , e exponent.

for example 0.25 converted to: 1.0 x 2^-2

note significant digits limited 23 bits.

in example 1.000001 converted 1.<20 zeors>101001... can take first 23 digits (1.<20 zeors>101). 0.000001 can start 23 digits first 1 (which bit 20th) , use exponent -20 , store number in higher precision.


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