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Re: g++/gcc : Floating point issue
abuzer.salik@tcs.com wrote:
I have an application which uses double values a lot. If I try to put say
401.74 in a double variable it is getting stored as 401.74000000000001
which creates problem in the calculations down the line. ( I am checking
these values using gdb debugger).
So, I am wondering if there is a way by which I can store the correct
values (i.e. 401.74) in the double.
No.
Only dyadic rationals (a rational number of the form a/(2^b) where a is
an integer and b is a natural number) have a finite binary expansion.
40174/100 = 200087/50 (and 50 is not 2^b for a natural number b)
See the links:
http://en.wikipedia.org/wiki/Binary_numeral_system#Representing_real_numbers
http://en.wikipedia.org/wiki/Dyadic_fraction
Do we need to look for another compiler/hardware or current setup can
handle this?
You can use an arbitrary precision numeric library, for ex. GMP
http://www.swox.com/gmp/
Regars,
Luca.