A more accurate data type than float or double? C++

Question

Does C++ have a more accurate data type than float or double, or do I just have to settle for the fact that my calculations will be off?

EDIT: As Mr. Lister has pointed out, my question is regarding the precision. It's a bit frustrating when you add two floats/doubles together and the number is off half the time comparing to the calculation done by hand.

Answer 1

In some compilers, and on some architectures, "long double" will give give you more precision than double. If you are on an x86 platform the x87 FPU has an "extended" 80-bit floating point format. Gcc and Borland compilers give you an 80 bit float value when you use the "long double" type. Note that Visual Studio does not support this (the maximum supported by MSVC is double precision, 64 bit).

There is something called a "double double" which is a software technique for implementing quad-precision 128-bit floating point. You can find libraries that implement it.

You could also investigate libraries for arbitrary precision arithmetic.

For some calculations a 64 bit integer is a better choice than a 64 bit floating point value.

But if your question is about built-in types in current C++ compilers on common platforms then the answer is that you're limited to double (64 bit floating point), and on 64 bit platforms you have 64 bit ints. If you can stick to x86 and use the right compiler you can also have long double (80-bit extended precision).

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