Bug or what?

Question

Hello, This is my serious problem: (In Visual Studio 2005 Fwrk 2 and Visual C# 2008 Express Fwrk 3.5)

For example:

double myvar = 0.78+1.33;

myvar = 2.1100000000000003

instead:

myvar = 2.11

And in my project, I can't use round function, and I don't want use float, because I need ALL decimals...

Saludos!

Answer 1

Computers represent everything using binary.  For decimal, use the Decimal type.  Try Wikipedia for clarification of binary arimethic.

Answer 2

Hi,

That's because machine use binary to store data.

double is store in:

1bit for sign
11 bits for Exponent
52 bits for Mantissa

double 0.78 in memory is :
       3f                 e8                  f5                   c2                       8f               5c      28     f6
0[011 1111   1110 ] [1000       1111 0101     1100 0010    1000 1111    ........

+   127-1=126     Mantissa is -1             1.000111101011100001010001111......
0.110001111......
0.5+0.25+0.15625+....=approximately 0.78 ,so there is rounding error and relative error in memory .

For more information , please see What every computer scientist should know about floating-point arithmetic

Harry

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Answer 3

Computers represent everything using binary.  For decimal, use the Decimal type.  Try Wikipedia for clarification of binary arimethic.

Ok, but how I use, Math library of C#, if it returns double values type... Is there an alternative to this library that works in decimal?

Answer 4

Which functions do you need to call in the Math library?
There's a few overloaded methods.

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Mark the best replies as answers. "Fooling computers since 1971."

Answer 5

Trigonometrics, Logarithmics, Sqrt, etc. Thanks for your time!!

Answer 6

This is my application, enjoy it! sorry by the language... ;)
Resolve ecuations like this for example:

-50+(20+10)-10*8E-13+54^2*(12-5)+cos5-sen84+Ln(23)

http://rapidshare.com/files/305665135/Calculadora.rar.html

Answer 7

This is my application, enjoy it! sorry by the language... ;)
Resolve ecuations like this for example:

-50+(20+10)-10*8E-13+54^2*(12-5)+cos5-sen84+Ln(23)

http://rapidshare.com/files/305665135/Calculadora.rar.html

Answer 8

Since it is scientific math, you'll want to use doubles.  Format your answers as you feel is necessary.